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graham.cluer2
Feb 10, 2015, 9:42:50 AM2/10/15
to croydo...@googlegroups.com
I was having problems trying to get by digital camera with a telephoto lens to point at Lovejoy. The trouble was that, although I knew roughly where Lovejoy was, I couldn't identify that bit of the sky through the camera viewfinder or on the screen. It was just too dark to see.
I found a place in the USA selling a red dot finder to mount on the hot shoe flash gun holder of the camera but it looked expensive and I didn't fancy paying import duty. So I made one.
I bought a hot shoe to tripod mount (niceEshop(TM) 1/4 Inch Tripod Mount Screw To Flash Hot Shoe Adapter For SLR Camera -Black) from Amazon for £1.59. This attaches to the hot shoe and is locked in place with one of the two knurled nuts.
I also got a hot shoe adapter, also from Amazon, (Kaavie Adjustable Hot Shoe Adapter with 1/4'' Screw Thread) for £4.59 including postage. The screw part of the previous item screws into here and is held securely by the other knurled screw. This top of this part has a vice-type fitting that will grip the red dot scope. It isn't a very firm grip so I first tried scoring a scratch on the red dot finder then, when I was totally happy, I got the Araldite out.
The finderscope was a standard Celestron red dot finder, I got mine again from Amazon for £26.90 but there will be cheaper ones around.
It seems to work!
JR
Feb 10, 2015, 10:29:32 AM2/10/15
to croydo...@googlegroups.com
Brilliant!
For an encore can you do a right angle viewer for a polarscope please?!
James
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William Bottaci
Feb 10, 2015, 2:30:20 PM2/10/15
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Graham, you can set up a little cottage industry and sell them for a
nice profit, for the many that may not do as you did but need one all
the same :).
I'm wondering if the same principle can be used to mount a green laser
pointer; something like a 6-inch aluminium angle with 1 cm a side and
elastic band. Jonathan ...?
James, is the illuminated disk diagram of Polaris and NCP set up only
for inverted vision?
Many thanks, William
https://groups.google.com/forum/?fromgroups#!topic/croydonastro/8hegjNTCeQQ
On 10 February 2015 at 15:29, 'JR' via croydonastro
nice profit, for the many that may not do as you did but need one all
the same :).
I'm wondering if the same principle can be used to mount a green laser
pointer; something like a 6-inch aluminium angle with 1 cm a side and
elastic band. Jonathan ...?
James, is the illuminated disk diagram of Polaris and NCP set up only
for inverted vision?
Many thanks, William
https://groups.google.com/forum/?fromgroups#!topic/croydonastro/8hegjNTCeQQ
On 10 February 2015 at 15:29, 'JR' via croydonastro
<croydo...@googlegroups.com> wrote:
Brilliant!
For an encore can you do a right angle viewer for a polarscope please?!
James
Brilliant!
For an encore can you do a right angle viewer for a polarscope please?!
James
On 10 February 2015 at 14:42, graham.cluer2 <graham...@gmail.com> wrote:
I was having problems trying to get by digital camera with a telephoto
lens to point at Lovejoy. The trouble was that, although I knew
roughly where Lovejoy was, I couldn't identify that bit of the sky
through the camera viewfinder or on the screen. It was just too dark
to see.
I found a place in the USA selling a red dot finder to mount on the
hot shoe flash gun holder of the camera but it looked expensive and I
didn't fancy paying import duty. So I made one.
I bought a hot shoe to tripod mount (niceEshop(TM) 1/4 Inch Tripod
Mount Screw To Flash Hot Shoe Adapter For SLR Camera -Black) from
Amazon for £1.59. This attaches to the hot shoe and is locked in
place with one of the two knurled nuts.
I also got a hot shoe adapter, also from Amazon, (Kaavie Adjustable
Hot Shoe Adapter with 1/4'' Screw Thread) for £4.59 including postage.
The screw part of the previous item screws into here and is held
securely by the other knurled screw. This top of this part has a
vice-type fitting that will grip the red dot scope. It isn't a very
firm grip so I first tried scoring a scratch on the red dot finder
then, when I was totally happy, I got the Araldite out.
The finderscope was a standard Celestron red dot finder, I got mine
again from Amazon for £26.90 but there will be cheaper ones around.
It seems to work!
Graham Cluer
I was having problems trying to get by digital camera with a telephoto
lens to point at Lovejoy. The trouble was that, although I knew
roughly where Lovejoy was, I couldn't identify that bit of the sky
through the camera viewfinder or on the screen. It was just too dark
to see.
I found a place in the USA selling a red dot finder to mount on the
hot shoe flash gun holder of the camera but it looked expensive and I
didn't fancy paying import duty. So I made one.
I bought a hot shoe to tripod mount (niceEshop(TM) 1/4 Inch Tripod
Mount Screw To Flash Hot Shoe Adapter For SLR Camera -Black) from
Amazon for £1.59. This attaches to the hot shoe and is locked in
place with one of the two knurled nuts.
I also got a hot shoe adapter, also from Amazon, (Kaavie Adjustable
Hot Shoe Adapter with 1/4'' Screw Thread) for £4.59 including postage.
The screw part of the previous item screws into here and is held
securely by the other knurled screw. This top of this part has a
vice-type fitting that will grip the red dot scope. It isn't a very
firm grip so I first tried scoring a scratch on the red dot finder
then, when I was totally happy, I got the Araldite out.
The finderscope was a standard Celestron red dot finder, I got mine
again from Amazon for £26.90 but there will be cheaper ones around.
It seems to work!
JR
Feb 10, 2015, 2:48:08 PM2/10/15
to croydo...@googlegroups.com
William
The polarscope is a basic refractor and does I believe invert the image. Inspired by Graham I had browsed and found that the popular diy solution involves a 1x power right angle adapter for a DSLR viewfinder. These go for about £30 on eBay or Amazon and come with a plate like connector which can be solvent welded on one side to a plastic plumbing fitting, eg a large diameter pipe stop end, with a suitable hole made in it. The viewer clips onto the other side.
Most of their descriptions are in Chinese English but I think they use a prism so give the same view as you'd see through the polarscope. They also rotate 360 degrees and you have a facility for focusing, plus of course have the raison d'être so you don't need to assume a position suitable only for a yoga adept.
Based on the experience of making a battery powered adjustable illuminator for my polarscope, the tricky part will be getting tube or fabricating a connector (in this case from right angle viewer to polarscope), of the right diameter.
James
Sent from my iPad
The polarscope is a basic refractor and does I believe invert the image. Inspired by Graham I had browsed and found that the popular diy solution involves a 1x power right angle adapter for a DSLR viewfinder. These go for about £30 on eBay or Amazon and come with a plate like connector which can be solvent welded on one side to a plastic plumbing fitting, eg a large diameter pipe stop end, with a suitable hole made in it. The viewer clips onto the other side.
Most of their descriptions are in Chinese English but I think they use a prism so give the same view as you'd see through the polarscope. They also rotate 360 degrees and you have a facility for focusing, plus of course have the raison d'être so you don't need to assume a position suitable only for a yoga adept.
Based on the experience of making a battery powered adjustable illuminator for my polarscope, the tricky part will be getting tube or fabricating a connector (in this case from right angle viewer to polarscope), of the right diameter.
James
Sent from my iPad
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William Bottaci
Feb 10, 2015, 3:23:59 PM2/10/15
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That reminds me, when I bought my Olympus 35 mm kit I also obtained
such an item (Olympus Varimagni Finder) for better focusing, having
magnifications of x1.2 and x2.5. Necessarily does not change the view
orientation. Not used it in years, now it will live again!
Many thanks, William
To view this discussion on the web visit
https://groups.google.com/forum/?fromgroups#!topic/croydonastro/8hegjNTCeQQ
On 10 February 2015 at 19:48, 'JR' via croydonastro
such an item (Olympus Varimagni Finder) for better focusing, having
magnifications of x1.2 and x2.5. Necessarily does not change the view
orientation. Not used it in years, now it will live again!
Many thanks, William
To view this discussion on the web visit
On 10 February 2015 at 19:48, 'JR' via croydonastro
<croydo...@googlegroups.com> wrote:
William
The polarscope is a basic refractor and does I believe invert the
image. Inspired by Graham I had browsed and found that the popular
diy solution involves a 1x power right angle adapter for a DSLR
viewfinder. These go for about £30 on eBay or Amazon and come with a
plate like connector which can be solvent welded on one side to a
plastic plumbing fitting, eg a large diameter pipe stop end, with a
suitable hole made in it. The viewer clips onto the other side.
Most of their descriptions are in Chinese English but I think they use
a prism so give the same view as you'd see through the polarscope.
They also rotate 360 degrees and you have a facility for focusing,
plus of course have the raison d'être so you don't need to assume a
position suitable only for a yoga adept.
Based on the experience of making a battery powered adjustable
illuminator for my polarscope, the tricky part will be getting tube or
fabricating a connector (in this case from right angle viewer to
polarscope), of the right diameter.
James
2015-02-10
William
The polarscope is a basic refractor and does I believe invert the
image. Inspired by Graham I had browsed and found that the popular
diy solution involves a 1x power right angle adapter for a DSLR
viewfinder. These go for about £30 on eBay or Amazon and come with a
plate like connector which can be solvent welded on one side to a
plastic plumbing fitting, eg a large diameter pipe stop end, with a
suitable hole made in it. The viewer clips onto the other side.
Most of their descriptions are in Chinese English but I think they use
a prism so give the same view as you'd see through the polarscope.
They also rotate 360 degrees and you have a facility for focusing,
plus of course have the raison d'être so you don't need to assume a
position suitable only for a yoga adept.
Based on the experience of making a battery powered adjustable
illuminator for my polarscope, the tricky part will be getting tube or
fabricating a connector (in this case from right angle viewer to
polarscope), of the right diameter.
James
Graham, you can set up a little cottage industry and sell them for a
nice profit, for the many that may not do as you did but need one all
the same :).
I'm wondering if the same principle can be used to mount a green laser
pointer; something like a 6-inch aluminium angle with 1 cm a side and
elastic band. Jonathan ...?
James, is the illuminated disk diagram of Polaris and NCP set up only
for inverted vision?
Many thanks, William
nice profit, for the many that may not do as you did but need one all
the same :).
I'm wondering if the same principle can be used to mount a green laser
pointer; something like a 6-inch aluminium angle with 1 cm a side and
elastic band. Jonathan ...?
James, is the illuminated disk diagram of Polaris and NCP set up only
for inverted vision?
Many thanks, William
JR
Feb 10, 2015, 3:26:06 PM2/10/15
to croydo...@googlegroups.com
Let us know if it works!
Sent from my iPad
Sent from my iPad
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Tim R
Feb 11, 2015, 12:16:44 AM2/11/15
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As it happens I have a lathe and a milling machine. I might be talked into making up a connector if I have a dimensioned sketch.
…
JR
Feb 11, 2015, 5:02:03 AM2/11/15
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Tim
What a fantastic offer (subject to successful persuasion of course!)
These links provide an overview of what others have done so you can judge what's feasible or might work better.
and see embedded video by Swubba in this link
best wishes
James
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Tim R
Feb 11, 2015, 5:16:01 AM2/11/15
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That looks straightforward enough. It also is a suitable task for a portable clockmakers’ lathe which might make logistics easier.
Two other things spring to mind. First why not use a webcam to get an image?
Secondly a piece of slightly oversized plastics tube with a slit in one wall could be held in position with a Jubilee clip could provide a quick and dirty solution.
JR
Feb 11, 2015, 9:29:17 AM2/11/15
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Tim
I am impressed by your tool collection! I think the next step is to get a right angle viewer off eBay so there is something concrete to consider for measurements.
The web cam solution apparently suffers from not being able to get focus (and there is another cable trailing). I like to get my laptop out in the garden at the last moment for the usb to serial control of guiding and for the guide camera itself. The condensation isn't good for it and I have it in a cool bag to insulate it a bit and retain the warmth from the CPU, but this makes it rather inaccessible. The actual alignment of Polaris in the little target circle takes me about 30 seconds now I know where Polaris is, the mount altitude is left fixed, and the tripod is levelled, so my eye, without bodily contortions, is fine for me.
For anyone else in a similar position to me, I find another huge frustration with a polar scope is collimating it perfectly, adjusting the three grub screws one at a time with a fiddly to fit Allen key. I get (almost) there after a very long time, and then by accident rather by design, even after discovering to adjust only half the error each time.
Checking the collimation today, I took out one of the grub screws and compared it to others dotted around on the telescope. The two thumb screws for locking eyepieces in place on the star diagonal (all my gear is Celestron) surprised me by being perfect substitutes, as was one off my finderscope. Changing one grub screw at a time for a thumbscrew, the joy of identifying easily the correct pair of screws to adjust and adjusting two screws at once to go in the right direction was an indescribable pleasure! All done in three minutes, and now it's spot on I should think it won't need doing again. Maybe I am easily pleased but I recommend the technique. I replaced the thumb screws with the grub screws one by one to avoid movement of the reticle, which was successful.
Unfortunately the screw heads protrude too far to get the protective cap over the polar scope eyepiece back on for a permanent solution. It tapers too much and perhaps thumb screws could come loose in a way that grub screws don't.
James
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