OR: June 18. Various observations from Henry Coe

[Mark Wagner]

II met my buddy Richard Navarrete at Henry Coe State Park Wednesday for a 3rd Q observing session. We've now spent around 30 years observing together, at Coe and other close-by (and not so close) venues.  Thanks to Richard for suggesting and setting up this get together last night.  We had a group of nine, which made for a really fun gathering.

Conditions were surprisingly good. Afternoon winds dropped to into slightly chilly but gentle breezes by astronomical dark.  I'll also note, how amazed I was to see sunset so far north over the coast range mountains to the west as June's Solstice was imminent.  Sunsets from the overflow lot always offer a strikingly beautiful prelude to observing.

A few of the attendees seemed unaware of the options to spend the night rather than drive home late.  so I'll mention that I used to sleep in my car there lot, but now take a prefer a campsite 1/2 mile further up the road. Either makes for a much safer drive home, rested and during daylight.

While setting up my 10" Dob I noted a surprising optical deficiency.  I forgot my primary mirror.  Oops.  I changed my focus to social.  There were a few 10" and 14" Dobs, two C11's, Richard's 127mm refractor, an NV and a few imaging only setups.  It was great seeing everyone enjoying the event, all sharing views.  Instead of the sounds of hooting owls, I was hearing the vibrant chatter of astronomy.  So I had the great and unexpected experience of observing all night through other people's telescopes.

A word about equipment.  Moving around some of the (mass manufactured) Dobs I found their motion stiffness insane.  I began calling one of them "The Mule" it was so stubborn.  Proper (and not very expensive) materials make a Dobsonian fun and easy to use, more like an enjoyable close slow dance than a night-long argument.  This stuff is an easy fix.

I experienced a Pi Finder for the first time. I believe they may result people remaining unfamiliar with the sky beyond a few alignment stars.  To my mind, learning the constellations provides a much more  satisfying experience.  It is a spectacular (and even sometimes challenging) map.  I found the Pi Finder's lighted display, up by the focuser, a major no-no.  Its literally observing with a night right where you're going to be looking.  I also saw a Starsense gizmo imaging objects, which was a curiosity but also looking at a "TV" screen.

The observing.  I expected to spend time with Richard and his 127, but freed from my own telescope, I was no longer a slave to the list.  I think I visited everyone and viewed through every visual scope.  What fun!

There was an NV view of M8 and M20 in a single field roughly 2 degree field through a 10".  The softness of M20's nebula, offset open cluster embedded, the expanse of open space to M8. Absolutely stunning.  If NV observing wouldn't kill my NV, I'd be NVous.

I had an amazing view of M17 though the 14".  I asked the owner if he'd like to try a narrowband filter on it, and got my Ultrablock.  The change in detail and depth of M17, the extended nebulae behind and under (and some in front of) the Swan's body, and the highly filamentary nature of the thick sections of nebula, truly mind-boggling.  Filter types used:  NPB, Ultrablock (from defunct Orion) and UHC.  There may be some locally people would part with if you ask, duplicates.

The last view of the night for me was thru Richard's refractor.  It was M22.  It glowed delicately in exquisite detail, floating in a wide field aside three bright field stars to its west, and as if mimicking them, three stars similarly surrounding the glob.  The globular itself showed aspects I'd never noticed; the southwestern quadrant appeared significantly brighter than the northeastern with what felt like a distinct diagonal demarcation line in brightness creating the effect.  In the bright portion's upper section was a cleave, diagonally entering upward toward the center from the western edge, a dark gap that closed in toward the glob's center.  The northeast section had dimmer stars, and to my eye in two equal lobes.  In other words, a dimmer area entering from the north creating hemispheres.  It looked oddly like the lobes of a brain.  Again, the the wide-field context all this detail within the object itself.  Astonishing. 

I left in the morning refreshed after several hours good sleep. It had been an excellent third-quarter observing session.  The drive down was a beautiful finish to the trip; the curving road descending  through literally carpets of quail that scattered as my car approached, a yawning fox sitting on the road shoulder, high-tailing it to the bush at seeing me. Deer, watching cautiously as I passed by.  Then a decent into the lingering fog.  It is a very enjoyable ride if you don't rush.

Maybe I should leave my mirror at home more often.  We'll see. I may have a newly coated 18" by next week's observing trip.

-- 
Mark

[Richard Navarrete]

Nice report, Mark. It was almost like the old days when that lot would almost be full of telescopes, and we’d spend half the time visiting each other and exchanging views.

You should start bringing packs of Teflon to sell, ready to install on those mulish scopes.

If all goes well, I hope to be at Coe again on Wednesday. Good seeing to those of you headed to GSSP next week.

Clear skies!

Richard

Sent from the all new AOL app for iOS

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac
 
Subscribers post to the mailing list at:
 
sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/6f117798-1906-451d-8631-5f5ac9297419%40gmail.com.

[Jay Freeman]

> On Jun 21, 2025, at 15:44, Mark Wagner <itsmar...@gmail.com> wrote:
>
> I experienced a Pi Finder for the first time. I believe they may result people remaining unfamiliar with the sky beyond a few alignment stars. To my mind, learning the constellations provides a much more satisfying experience. It is a spectacular (and even sometimes challenging) map. I found the Pi Finder's lighted display, up by the focuser, a major no-no. Its literally observing with a night right where you're going to be looking.

PiFinder allows adjustment of display brightness at any time: I quote from its documentation: "The PiFinder is designed to allow you to adjust the brightness of the screen and keypad at any time: simply hold down the SQUARE button and push + for brighter, or - for dimmer. In a dark sky site, you can turn the brightness down to preserve your dark-adapted vision."

I agree with Mark's comments about the satisfaction of learning the constellations: I started out by doing that, and am glad I did. On the other hand, after more than half a century of trying to remember where Lacerta is and how to tell Hydrus from Hydra, I sometime find myself wanting to get on with an observing program, and for that purpose, PiFinder is the best $500 I have ever spent on astronomy equipment. With it, you can usually go from one object to another half way across the sky in less than ten seconds, and find it in the field of a low to medium magnification eyepiece right away. PiFinder has another, perhaps less well-known advantage for observing with small telescopes in cramped quarters, like suburban yards crowded by trees and deluged with street lights: Once it is turned on and aligned with your telescope, it stays aligned until turned off. You can pick up your grab-and-go instrument (with PiFinder attached), sling it and its tripod over your shoulder, walk across the yard to a shaded spot where no trees get in the way, set the telescope down again, and PiFinder will continue to tell you how to point the telescope to find the object.


-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Mark Wagner]

Richard,

What I see going on this new moon in TACos traveling from San Diego to GSSP,  TACos driving to a Bortle 1 in Nevada, going to Tranquility Base toward in the Santa Lucia, Fremont Peak, Coe and undoubtedly some with be at Lake Sonoma.  What a group!

Jay - I am not knocking DSC type finders of any kind.  But the sky is a more robust and exciting place when its more than just the objects buried within.  The value in less than easily usable skies is well noted - I am about to put old school manual setting circles on my 10" for at home to serve as personal guide dogs.

[Jamie Dillon, DDK]

The Swan is always fascinating. I've done a sequence more than once, looking at it unfiltered, then with an OIII and an Ultrablock. Intricate in each view.

You got onto a short list for major forgetting, Mark. Remember Rashad driving from San Francisco to the Peak, realizing he hadn't packed the tubes for his Dobs. He said bad words, did the round trip to the City, got back to the Peak and had a good observing night.

Once at the Peak I'd forgotten my eyepiece case. The Observatory was open, so I got to cadge an eyepiece. No red light though. Couldn't use my paper charts.

My personal best was forgetting shoes on a Lassen trip. This was Liam and me on the trip. Had all the astro stuff, camping gear, food, no shoes. The sandals I was wearing would not have done at Bumpass. Fortunately, Gottlieb and I have similar feet and he had an extra pair of sneakers. Phew.

[Mark Wagner]

Jay... can you see Hydrus from your backyard?   And, Hydra is kinda big, Hydrus kinda small.  As you know.

I am astonished to learn you can relocate your telescope and PiFinder still keeps accurate locations.  Awesome.  I just wish it were possible to observe with starlight being the only light viewed.

[Mark Wagner]

Wanted to show the portions of M22 that stood out so clearly in the 127mm scope, aside from the overall globular which in itself was spectacular.  This sketch is by Jeremy Perez, who ran Astro Sketch of the Day (ASOD) for many years.  It was in a 6" f/8 Dob from Anderson Mesa AZ (a Jamie fave).  The 8 o'clock line points at the dark lane intruding from the upper right.  4 o'clock is the lines of stars that seemed to bisect the object, dividing it into denser/brighter condensation, and dimmer side.  Top left and right are lobes, with the dark intrusion entering for 12 o'clock.

The detail was mesmerizing.  I'm accustomed to seeing M22 blown up big and bright in 10-18" scopes!

[Steven R.]

The PiFinder alignment memorizes the offset between the PiFinder camera and the telescope boresight axis, which is why the PiFinder/scope ensemble can be moved at will without disrupting the alignment. Basically the same argument as why your RACI alignment is still good after you relocate your scope.

Hopper is an alternative to PiFinder that uses your phone for its UI. After you've used Hopper's push-to guidance on a dimly lit red OLED phone screen (OLED means no LCD backlight leakage), you can pocket the phone and not worry about any stray light.

Hopper is out of stock at the moment at cs-astro.com. We'll have a new batch ready in a month or so.

Clear skies,

-Steven

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac
 
Subscribers post to the mailing list at:
 
sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/55722b96-d65f-4b2b-be2d-5da7d5b8802fn%40googlegroups.com.

[Richard Navarrete]

Jay is the Chuck Norris of astronomy . He doesn’t look for Hydrus, Hydrus looks out for Jay.

Richard

Sent from the all new AOL app for iOS

[Richard Navarrete]

That’s really cool, Mark. That was a great view, and a great choice for a final object to observe .

Richard

Sent from the all new AOL app for iOS

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac
 
Subscribers post to the mailing list at:
 
sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.
To view this discussion visit

https://groups.google.com/d/msgid/sf-bay-tac/5e133e5a-4039-474c-bf9c-7c184f56aba6n%40googlegroups.com

.

[Mark Wagner]

Steven,

I do find the put it in your pocket utility more desirable.  You are effectively saying the screen is only active during moves, right?

Is csastro a local bay area vendor?  Do you observe locally (South Bay), I'd like to see a Hopper in operation.

Thanks,

Mark

"Always take the scenic route."

You received this message because you are subscribed to a topic in the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/sf-bay-tac/DiFr09UHeKM/unsubscribe.
To unsubscribe from this group and all its topics, send an email to sf-bay-tac+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/CANaV7GEmu6YLquWZ8eWE3aSJWgs6eoBfZi8yFDD3iEu-OH32Fg%40mail.gmail.com.

[Jay Freeman]

The big break in learning to tell Hydrus from Hydra was the dawning realization that Hydrus is not visible from the latitudes where I usually observe. This observation led to my next conclusion, that the easiest way to make sure about Lacerta was to go far enough south to be certain I couldn't see it.


I believe PiFinder works like this: When it is switched on, it figures out from GPS where it is, and then looks at the sky to find a recognizable pattern of stars. The search is helped by the GPS fix and by the software's assumption that one axis of the camera's image chip is more or less horizontal, but even so, it can take a few minutes to figure it out. PiFinder is then prepared to present on its screen an image of the brightest stars near the center of its field, after which you point the telescope at one of them and push a button to tell PiFinder which one it is. The instrument then knows where the telescope is pointing, and you are off and running.

On a recent setup, I pointed the telescope generally at Scorpius, and PiFinder presented alpha, sigma and tau Sco as choices, labeled with numbers 1, 2, and 3 in order of descending brightness. So I pointed the telescope at Antares and pushed "1".

PiFinder then uses internal gyros -- electronic ones -- to keep general track of changes in the direction in which it is pointed. Thus further plate-solving can proceed more rapidly, even after a fast hand-slew, since the instrument will always already know roughly where it is looking. That mechanism also works when you sling the tripod over your shoulder and carry it off, as long as you do not turn PiFinder off or disrupt the mechanical connection between it and your optical tube assembly.

The operation of these two mechanisms can sometimes be seen: During a fast slew to a new object, the "turn it this-a-way that much" directions shown on the PiFinder screen will change rapidly, but sometimes, after you have zeroed in according to the screen, the display will change again after a bit. What is happening is that the first zero-out was based on direction changes reported by the gyros, but the second resulted from a new actual plate-solve. This effect is particularly noticeable when there are many street lights, or haze, or the sought-after object is near the horizon.

I often check out small telescopes by chasing Messier objects, and I regularly find myself impatiently waiting for something that is about to rise. In such circumstances, PiFinder will often -- properly -- tell me to point the telescope below the horizon, whereupon I wait patiently, tweaking the slow-motions to keep the object's position centered, until I see it peeking through the tree branches at the top of the nearby ridge, or whatever. Globular clusters thus observed resemble squirrel's nests in which someone has left the night light on.

How fast is it? Last night I trotted out a newly-bought used Orion ST80 (80 mm f/f doublet refractor) for first light, set up on a simple altazimuth mount with PiFinder attached. I was using an 8 mm Konig eyepeice that gave a field of about a degree and a quarter at 50x, and PiFinder always put my target well within the field. In two and a half hours I logged 82 Messier objects, and I probably spent more time checking them off on a list and making notes than I did at the telescope. With judicious use of the clutches and fast twirling of knobs, it typically took less than fifteen seconds to go from one object to the next, even when slewing through more than 60 degrees.

-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Jay Freeman]

The problem with Karate-chopping a galaxy is the gnawing concern that it might somehow be able to retaliate ...

-- Jay Reynolds Freeman, Deep-Sky Weasel, whose black belt is a dark nebula

---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Steven R.]

Mark,

Yes, we're in the Bay Area. I've not been to any TAC outings (I'm relatively new to lurking on this list), but lately I've been to some Santa Cruz Astro Club outings. I'd be happy to join you at an upcoming TAC outing to meet you and other TAC friends and let you try Hopper out.

Cheers,

-Steven

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/CAG72LjAQ6RJSTj8G67jZuycVHe6vSdcZrsqr28ifTuiFKS%2Bv%3Dw%40mail.gmail.com.

[Richard Navarrete]

Just give it an Einstein’s Cross and you’ll be good.

Richard

Sent from the all new AOL app for iOS

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac

Subscribers post to the mailing list at:

sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/CB56E86C-7B7B-46E6-9850-D59F51617AF7%40mac.com.

[Steven R.]

The interaction between PiFinder's gyro-determined pointing estimate and the Cedar plate solving is a little different than what you described. In particular, the gyro-determined rough pointing is not used as an input to the plate solver; every single plate solve is "blind" with no priors, not even the previous plate solution.

The Hopper device I mentioned previously also uses Cedar plate solving, and it omits the gyro. Thus, while the telescope is moving quickly, Hopper blanks out its display of the telescope position (because it cannot plate solve streaked images), whereas PiFinder uses its gyro integration to provide a somewhat accurate position display even during fast motion. For both products, once telescope motion becomes sufficiently slow, plate solving immediately resumes providing exact positioning.

Clear skies,

-Steven (Cedar developer)

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac

Subscribers post to the mailing list at:

sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/7D34988E-38A3-41B7-BEE5-8B856D07251D%40mac.com.

[Jay Freeman]

I have not seen Hopper, of course, but blanking the display while the telescope is moving quickly might be a serious impediment to its use: When I use PiFinder, the instantaneous update of the pointing direction, provided by the gyros, is invaluable for quick setting on new positions. It is like operating a combination lock -- you turn the dial and stop at the number you want -- that would be difficult if you couldn't see the numbers while the dial was turning.

-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Steven R.]

Yes, PiFinder is superior to Hopper in that respect. In practice using Hopper, the motion pauses needed to get updated push-to guidance are very brief, and if you're moving sufficiently slowly (e.g. once you're near the target) the plate solutions don't drop out.

-Steve

--
Observing Sites, Observing Reports, About TAC linked at top of:
https://groups.google.com/forum/#!forum/sf-bay-tac

Subscribers post to the mailing list at:

sf-ba...@googlegroups.com,
---
You received this message because you are subscribed to the Google Groups "The Astronomy Connection (TAC)" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sf-bay-tac+...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/B02C7BA0-D468-4BB6-83D5-41ABE1ADF5D3%40mac.com.

[Mitchell Koerner]

Just giving my 2c here.

I've used a borrowed hopper but not a pifinder on my 10" dob when Steven was at the most recent "spring fling" calstar.

The direction drops out while I'm moving and then comes back in what felt like less than a second.

I was making my initial slew based on the sky and constellations with my rigel quick finder and then using the hopper at the end instead of star hopping in a finder scope.

With my technique, I really didn't care that I had to stop to see where my scope view was on SkySafari. It was still WAY faster than stopping and star hopping and I doubt a gyroscope would have sped up my observing more than 1s per observation.

I havent used other techniques or directly compared to a pifinder so take my experience for what it is. No more, no less.

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/CANaV7GES7FsPiLWDNEjuoRigp8EmKzB_zkgymXZ1tnvQ9Xxj0A%40mail.gmail.com.

[Jay Freeman]

For the record, I just tried PiFinder's light-level adjustment facility. (I keep forgetting to use it while observing, because my usual site is sadly not very dark -- only about Bortle 4.) I took it into a bathroom with no windows, turned off the lights and closed the door. Pushing the buttons does not turn the light completely off, but in my opinion it gets dark enough not to interfere even at sites noticeably darker than Bortle 4. I suspect it would not be an issue at the outer parking lot at Coe unless the marine layer was really thick, though it might have been too much for Bumpas Hell at the old Lassen star parties.

Of course, PiFinder is lumpy enough that you could always hang your hat over it.

-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

> On Jun 22, 2025, at 07:48, Mark Wagner <itsmar...@gmail.com> wrote:
>

> [...] PiFinder [...] I just wish it were possible to observe with starlight being the only light viewed.
>

[Jay Freeman]

Sounds like that technique would work fine for many people. I myself have never had any use for red-dot finders (I look through the telescope eyepiece with glasses off; I am sufficiently near-sighted that I can't see sufficiently faint stars with glasses off to make good use of a red-dot finder, and it is inconvenient and drop-the-glasses-prone to keep putting them on and off while observing.) When I am using PiFinder, I rarely use the (regular, straight-through) finder at all after initially aligning the telescope.

-- Jay Reynolds Freeman

---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Steven R.]

I've got a new batch of Hoppers up on the cs-astro.com site. LMK if there's interest in a demo/tryout at an upcoming TAC outing. Hopper works under light polluted sky, so something near me (Cupertino) is fine for trying it out; I'm also happy to venture further out for better sky conditions.

Cheers,

-Steven

[Steven R.]

An update on Hopper: we have added IMU sensor fusion so now Hopper provides position estimates even during slews. When motion slows or stops the position estimate is automatically replaced by the accurate plate solution. The IMU sensor fusion works regardless of how the Hopper is mounted on your telescope, and works for both alt-az and equatorial motions.

I'll be at CalStar in April 2026 with a bunch of Hoppers for folks to "buy to try"; you can return it to me in the morning for a full refund if you don't want to keep it.

Cheers,

-Steven