Shooting the moon tonight

[Alienfox]

I am hoping to get out tonight to grab a few shots of the moon tonight, I am thinking of using my Skymax-90 f1/125, but not sure if to use my nikon or capture video?

I can try both, but wondered if anyone has a preference when using a simular scope?

[JamesF]

With my 127 Mak I put the DSLR straight on the back of the OTA and capture still frames to stack.  If you want a full disc image that's probably the easiest way.

No reason you can't do either though.

James

[Gutross]

With my 127 Mak I put the DSLR straight on the back of the OTA and capture still frames to stack.  If you want a full disc image that's probably the easiest way.

No reason you can't do either though.

James

for still frame stacking, do you still use registax? or another program?

[nightfisher]

I would go for dslr prime focus, take as many shots as you can and look at running them through pipp then registax

[JamesF]

for still frame stacking, do you still use registax? or another program?

I do, yes.  I did a little write-up some time ago about it.  I'll see if I can find it again.

James

[JamesF]

Here you go: http://stargazerslounge.com/topic/184192-full-disc-lunar-imaging-with-a-dslr/

James

[Gutross]

Here you go: http://stargazerslounge.com/topic/184192-full-disc-lunar-imaging-with-a-dslr/

James

thank you

[Alien 13]

I will be very interested in your results I have always fancied a 90mm mak.

Alan

[Alienfox]

Well I screwed up, had problems with the focusing, needed to stack the images but because of the size of scope I could not get the whole moon in one frame so had to make a stitch with 2 images.  However, I think I may try my 150 reflector tomorrow if it remains clear.

[JamesF]

I don't understand why you'd not be able to get the image in one frame.  I have no problems doing so with my 450D on the 127 Mak, which has a 1500mm focal length and therefore produces a larger image than your 1250mm OTA.

How are you connecting the camera to the OTA?

James

[Alienfox]

Hi James, I am connecting the camera directly to the back of the scope? 

[JamesF]

Hmmm.  This is a standard APS-C DSLR?

James

[Alienfox]

I know, strange, but I forgot to mention I had the star diagonal connected as well?

[JamesF]

Ah, that would make a difference.  The focal length of a Mak (or SCT) is not fixed.  It will change depending on where the image plane is.

I don't know about the 90, but the 127 has a T-thread on the visual back, so I put a T-adaptor on the camera and fit it that way.  I have a picture somewhere.  I'll see if I can find it.  It's probably better than using the diagonal because it will be more rigid.

James

[JamesF]

Here we go.  This is from a solar imaging session, but with the exception of the filter I use pretty much the same setup for both.

[Alienfox]

Ha Ha, thats what i did wrong then, I will try again without the diagonal fitted tonight clouds permitting.  Thank you James.

[JamesF]

You may find you need to move the focuser knob quite a lot to account for the change in camera position.  My recollection is that from "full out" to "full in" there are over twenty revolutions of the focuser knob on my 127.

Talking of which, there are a few different mods to help with focusing (you can see in the photo that I've motorised mine), but an old favourite that's simple and allows you to change the focus in small amounts fairly easily is to put a clothes peg (the type with a spring) on the focuser knob once you get close.  You can then just push the end of the peg around.  As you don't have to touch the OTA to do that it also helps reduce the wobble you get when adjusting the focus.

James