Milky Way at Kenley, again - 5 attached

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William Bottaci

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Sep 7, 2021, 12:35:40 PM9/7/21
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At Kenley Observatory in the last days of August, Kevin and I managed to capture a wide-angle portion of the Milky Way in Cygnus. Conditions identical to a month previous; same direction, same gibbous moon in the same place, 90 degrees away in the east. Also same equipment but exposing for 12 rather than 9 seconds, as the tracking is easily good enough.

Canon 70D dSLR, 20 Mpx cropped sensor, 24 to 70 lens set to 50mm, f/4, 50x12 secs at ISO 800 on fixed tripod.
An Omegon LX clockwork drive was used for tracking.

This time we set a longer remote timer delay of 30 seconds between exposures so the exposure time of 12 seconds (+12 s dark) was not truncated. Again used the noise reduction setting, which results in the camera exposing for a further 12 seconds after each shot with the shutter closed; these are the darks.

Polar alignment was by eye through a short plastic tube looking at Polaris, but drift over the 50 exposures was not much. Field of view would be close to 30° diagonal (26° by 17°).

Raw CR2 files processed in Deep Sky Stacker, this time set to best 100% so all 50 were used. Many satellite tracks were averaged out by DSS so not visible. No aircraft.

Tiff file processed in GIMP (histogram stretching, contrast, saturation). Image scaled to 4K, best viewed on a 4K TV or monitor.

Plate solved using astrometry.net. This time the view is further to the north and a little east so the brightest star is Deneb, bottom right of centre.

An estimated 35,000+ stars in the field, but you need to zoom in on the original. The Milky Way runs from just below the top left corner to bottom centre.

A star of note:
 - The well known 'The/Herschel's Garnet star', or Erakis, formally known as Mu Cephei, is to the top left, more or less diametrically opposite Deneb. By any standard a giant star, estimated larger then Betelgeuse, one of the largest and farthest stars seen by the naked eye.
https://www.star-facts.com/mu-cephei/

 - There is another red star half way between Deneb and 51 Cyg, the reddest looking star in this photograph (you may need to zoom in to see it, but it's worth it), but only because at magnitude ~10.4 (var ±3.0) it is not overexposed like Mu Cephei. Known as: TYC 3578-2382-1, V Cyg, it is a carbon star. At about 1,200 light years it is half the distance of Herschel's Garnet star.
A crop of the region shows it to the top left.
An identical crop is from a single exposure - more noise, less stars.

Messier 39 is between 71 Cyg and 81 Cyg but to the right - Messier objects are not shown in astrometry plate solves. It really needs a higher magnification. Messier 29 is seen just below Sadr in the photograph from a month ago.

Fans of Messier 39 can order the T-shirt here...
https://www.redbubble.com/i/t-shirt/Messier-39-Open-Star-Cluster-in-Cygnus-by-galactichunter/28744864.1YYVU

Thanks for looking, William

=Cygnus_2021-08-27_KenObs_WB_P_2160.jpg (2,736K)=
=Cygnus_2021-08-27_KenObs_WB_P_1600_5640928.jpg (675K)=
=Cygnus_2021-08-27_KenObs_WB_P_1080.jpg (414K)=
=Cygnus_2021-08-27_KenObs_WB_P_V Cyg.jpg (157K)=
=IMG-70d_44400_2021-08-27_KenObs_WB_P_V Cyg.jpg (82K)=
Cygnus_2021-08-27_KenObs_WB_P_2160.jpg
Cygnus_2021-08-27_KenObs_WB_P_1600_5640928.jpg
Cygnus_2021-08-27_KenObs_WB_P_1080.jpg
Cygnus_2021-08-27_KenObs_WB_P_V Cyg.jpg
IMG-70d_44400_2021-08-27_KenObs_WB_P_V Cyg.jpg

Kevin Phillips

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Sep 7, 2021, 2:53:25 PM9/7/21
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I was really impressed what one can do with a dslr. Amazing photos qell done william.


From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of William Bottaci <w.bo...@gmail.com>
Sent: Tuesday, September 7, 2021 5:35:13 PM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: [croydonastro - 6968] Milky Way at Kenley, again - 5 attached
 
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JR

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Sep 8, 2021, 3:29:33 PM9/8/21
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Hi William

Good stuff.  I opened it on my ipad using Photoshop Lite and pressed the autoenhance button.  Amazing.  Very skilful.  

Looks more like 36,000 + than 35,000 stars to me.  

James




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On 7 Sep 2021, at 17:35, William Bottaci <w.bo...@gmail.com> wrote:


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<Cygnus_2021-08-27_KenObs_WB_P_2160.jpg>
<Cygnus_2021-08-27_KenObs_WB_P_1600_5640928.jpg>
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<Cygnus_2021-08-27_KenObs_WB_P_V Cyg.jpg>
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tcos...@gmail.com

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Sep 10, 2021, 3:27:53 AM9/10/21
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Hi William

Excellent images . The stars are crisp and nicely coloured and I love the massive field of view. I’ve toyed with the idea of putting my DSLR on my paramount to take these sorts of shots, but I’ve never got around to it, even though I got the saddle to mount the camera! One day maybe.

Thanks for sharing and also to James for his contribution!

Tim C

image001.jpg

William Bottaci

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Sep 10, 2021, 8:42:24 AM9/10/21
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Thank you all.

James, clearly you're processing has made a lot more stars evident and I may have been conservative on the number of stars. I didn't want to overdo it but I'll have another go, as now my processing looks a little lame.

Looking at your version, centre of bottom edge, there is some redness, so comparing with a star atlas (that uses photographs rather than charts) I can now see that it's a part of NGC7000, the North American nebula. You pointed out that it was in the top left corner of the image of a month ago, so I can see how these two are positioned in the sky.
My camera not being modded* I'm not going to target it. Any astro camera leaves this open. At least one member, John, had his dSLR Canon 40D modded and he's produced much better images of these objects.

Tim, I know that using your mount for this kind of imaging during a clear night may be a missed opportunity for your more sophisticated equipment, but you might consider using a different mount, as anything simple will suffice. And then once you set the controls it just runs, much like your existing setup, so you will easily be able to do both at the same time.

For anyone, there are many simple trackers, and I use this, which is about the simplest (available even locally in Purley, courtesy of Bernard):
https://www.modernastronomy.com/shop/mounts/omegon/omegon-mount-mini-track-lx2/
and there is a review linked in the first paragraph. Operation is carbon neutral :).
It sits atop a simple photographic tripod.

A more recent model is the LX3, same page, which is more expensive but has a polar scope instead of a tube, and general enhancements. I find the tube more than accurate; over a run of 35 minutes using 70 mm on an object at declination 25º the field shifted about 2%, which can be ignored during stacking. 'Ignoring' means the whole of all 50 frames can go into the final result, not just their common area/intersection.

* At least Canon cameras have a filter in front of the sensor, one purpose is to cut off the red end of the spectrum else it'll be too sensitive towards red and would show unnatural colour. This more closely matches our eyes. This is fine, but for astrophotography it just about cuts off the important Hydrogen alpha light, of which many deepsky objects shine.
Historically at least Kodak arranged the chemistry of their emulsion films for the same purpose. In B&W photography they reasoned that women's lips look better darker, not a light grey.

William




On Fri, 10 Sept 2021 at 08:27, <tcos...@gmail.com> wrote:
Hi William
Excellent images . The stars are crisp and nicely coloured and I love the massive field of view. I’ve toyed with the idea of putting my DSLR on my paramount to take these sorts of shots, but I’ve never got around to it, even though I got the saddle to mount the camera! One day maybe.
Thanks for sharing and also to James for his contribution!
Tim C



On Wed, 8 Sept 2021 at 20:29, 'JR' via croydonastro <croydo...@googlegroups.com> wrote:
Hi William
Good stuff.  I opened it on my ipad using Photoshop Lite and pressed the autoenhance button.  Amazing.  Very skilful.  
Looks more like 36,000 + than 35,000 stars to me.  
James
[]




On Tue, 7 Sept 2021 at 19:53, Kevin Phillips <thewels...@live.com> wrote:
I was really impressed what one can do with a dslr. Amazing photos qell done william.



2021-09-07
Cygnus_2021-08-27_KenObs_WB_P_2160.jpg
Cygnus_2021-08-27_KenObs_WB_P_1600_5640928.jpg
Cygnus_2021-08-27_KenObs_WB_P_1080.jpg
Cygnus_2021-08-27_KenObs_WB_P_V Cyg.jpg
IMG-70d_44400_2021-08-27_KenObs_WB_P_V Cyg.jpg

JR

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Sep 10, 2021, 9:59:46 AM9/10/21
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Well done spotting the N American nebula William.  Lost on me completely, as I'm red green colour blind.  

Hidden depths in that image.  I look forward to seeing the results of proper processing.  All I did was use enhance, which you also get on most smart phones and works wonders.

cheers

James

Sent from my iPad

On 10 Sep 2021, at 13:42, William Bottaci <w.bo...@gmail.com> wrote:


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