HQ Camera and Astrophotography

[JovianPyx]

I would love to get an HQ camera to try astrophotography, but I can't find enough information. I have two telescopes, Celestron C-90 and C-8. I have a clock drive on an equatorial mount. I've used both with a standard film camera at prime focus. I have the T-ring for a Yashika camera body. While the equatorial mount can move just the HQ camera, I'd like to use long lenses. The C-8 is 2000 mm and the C-90 is 1000 mm.

Is there a T-ring I can use with the HQ camera?

If not is there an adapter for the Yashika T-ring to attach the HQ camera?

Or what do I need to attach the HQ camera to a Celestron telescope?

[xkubazz]

You need T-mount to C-mount adapter, like those:
https://www.teleskop-express.de/shop/pr ... hread.html
https://www.amazon.com/dp/B079ZQ6QTC/re ... UTF8&psc=1
https://www.astroshop.pl/adapter-projek ... ead/p,5870

[JovianPyx]

Thank you very much.

I looked at all three and they look very different. I can't tell if they all would put the camera at the same point in the light path.

Is there a difference between these that is important?

My location being USA, I'm most interested in the one at the Amazon site, so all other things being equal, I'd get that one.

[xkubazz]

I don't really know, I use photo lenses for astrophotography - but I just read that those Celestrons have simple 1.25 inch threads and you can use straight 1.25 to 1 inch (C-mount) adapter.
https://www.amazon.com/SVBONY-Camera-Ad ... ref=sr_1_7
https://www.amazon.com/Astromania-Camer ... ref=sr_1_3

My guess is that this would be best option.

[JovianPyx]

Thank you very much again, stuff on order now. Should be a blast playing with this and one of my Pi boards (also getting 2 pi4b with 8G).

[cgioconda]

I've been experimenting with the HQ camera and a 1.25" telescope adapter (to perform prime-focus photography) but I'm having issues focusing the image properly with my 8" Newtonian scope. Admittedly it's a fast scope (f/4) but I had hoped to have better results.

Any suggestions?

[HermannSW]

but I'm having issues focusing the image properly ... Any suggestions?

Use naushir's new "--focus" raspistill option, bring the displayed value to maximum, and you are focused:
viewtopic.php?f=43&t=276411&p=1674908#p1674803

[xkubazz]

Use Bahtinov mask: https://en.wikipedia.org/wiki/Bahtinov_mask
You can buy one, matching size of your telescope (about 20$ on Amazon) or do-it-yourself: http://astrojargon.net/MaskGenerator.aspx
For more information check astrophotography forums like CloudyNights.

I use DIY one in front of 200mm photo lens, it works okay but cutting 1mm slots using knife in plastic was pretty tough and time consuming. With bigger aperture, slots will be bigger and easier to cut.

Few images I got so far: https://terramex.neocities.org/astro/index.html

Software focus detection was not precise enough for me due to noise, I could not get better results than with just eyeballing focus.

[cgioconda]

Still not sure I’m following - I’m not using a lens.

The HQ camera is connected to an adapter that lets me use the camera directly in the focuser without an eyepiece.

How would the mask work then?

I appreciate the help btw!

[xkubazz]

You put it in front of your scope like this:

source: http://www.weasner.com/lx200acf/accesso ... ike-a.html

Then you enable preview from camera and manually adjust focus until three diffraction lines cross in single spot.

source: http://astroneophyte.blogspot.com/2018/ ... -mask.html

Once your scope is focused, you remove mask and start taking pictures.

[HermannSW]

Then you enable preview from camera and manually adjust focus until three diffraction lines cross in single spot.

source: http://astroneophyte.blogspot.com/2018/ ... -mask.html

Once your scope is focused, you remove mask and start taking pictures.

Sounds wonderful.
But it seems to be for telescope only.
For pinhole camera with 70mm focal length and aperture 1.6mm the tool creates a filled black circle.
For 35mm focal length and 16mm aperture a filled black circle is generated as well.

[xkubazz]

General idea works with lenses too, but on smaller optics pattern is less noticeable. On 200/2.8 full frame lens it is already barely visible, but just enough to get perfect focus (might be due to my poor cutting skills).

For 35mm focal length and 16mm aperture a filled black circle is generated as well.

For smaller lenses set "Bahtinov factor" to 50 and "Structural bar thickness" to 1mm. Mind you, for 35mm with 16mm aperture the bars will be 0.4mm thick - impossible to cut out without laser cutter or vinyl plotter.

For such small size Y-mask should be better and easier to make

source: https://www.cloudynights.com/topic/2245 ... sing-mask/


source: https://stargazerslounge.com/topic/2804 ... vs-y-mask/

It would not work with pinhole camera, as pinhole lens already has infinite depth of field and changing distance between hole and sensor only changes its focal length.

[billgs]

I cut my first Bahtinov mask from a plastic flower pot saucer.
It was for a 200mm reflector and took forever. More recently
I have inkjet printed masks on clear film and glued a second
clear sheet on the ink side to give some protection. A short
tube made from a narrow strip of card is then taped to the
mask to enable it be fitted to the o/d of the objective lens
or lens hood.

I'm looking forward to trying the "--focus" raspistill option
on moon "Close-ups".