Newbie learning how to photograph the Moon.

[blackrat3403]

Hello everyone, I'm hoping to use your collective knowledge to help me further this little hobby of mine; started by my wife much to her own disgust now.

I've been trying to get some good close up shots of the moon. I'm getting there, but have reach a point where I don't know what is going wrong or what to do to correct things.

So here's what is probably my best shot so far:

I'm using a Nikon D3100 DSLR

Celestron T-adapter 1.25"

T2 for Nikon

and (this is the embarassing bit)

a Jessops (TA1100-102) Reflecting scope.

As you can see by the photo the shot is slightly out of focus in places and not particularly sharp.  My question is thus:

Is it my equipment causing this and if so which part. Or is it my camera settings (and trust me I've played around with them, this is 1 of about 500 photos). Could it be caused by atmospheric conditions, i'm shooting from Frimley, Surrey, UK. Or finally is it something I could rectify with computer editing (which is another story)

Thanks for taking the time to read this.

Wayne

[nightfisher]

I think you have a few issues, is the telescope in good collimation, also you need to make sure its all pretty steady at moment of capture, also work on the focus, take some time with this, if you can use the zoom feature to check focus before taking the shot, and use the 2 second timer on the camera to reduce shake

[blackrat3403]

I'll have to check the collimation, that hadn't occurred to me.

I've tried my best to keep it steady. It was shot on a relatively calm night and I use a wired remote shutter release. Because of this I haven't been using the 2 second delay, but I can try with that next time. The Jessop tripod isn't great, I appreciate that. 

As to the focus, this has been my biggest stumbling block, I've taken multiple shots at slightly different focus, but none have been as clear as this or have displayed similar results. I've used the live view finder on occasion to check the focus and has always looked pretty well focused.

[ronin]

Bit odd, how long is the tube bit of the scope?

[blackrat3403]

The Tube is about 650mm.

[Astrosurf]

Hi Wayne, if you see here the scope's not very well thought of. Sorry! It may well be the best you can get with it, although I'm not familiar with the scope.

http://stargazerslounge.com/topic/129085-first-scope-a-little-advice-needed/

Alexxx

[ronin]

From the specification I assume that 1100 is the focal length and 102 is the mirror diameter.

The problem is you cannot get 1100mm in a 650mm tube.

This means they use a short focal length mirror then put a barlow in the focuser unit to get the longer focal length.

The design is called a Bird-Jones and is in principle not bad IF good matched optics are used as the barlow.

However mass produced units do not use good matched optics.

So you do not get the image quality that you really expect.

Sorry to say there is no real answer to the problem.

[JamesF]

Certainly the scope may not be the best, but with some perseverance you may well be able to do better.  Once you can get a reasonable single frame then you can progress on to stacking and suchlike to improve the image even more.

There is what looks to me to be a small amount of colour aberration in the image that you may be able to do nothing about, but given a good clear night I think what you really need to work on first is focus.  I'm guessing that the image above wasn't taken on the best of nights given the slight haze around the Moon, but it does look like the focus may not be the best anyhow.  Some faults can be worked around, but if you can't get really good focus you're going to struggle.

This might help in terms of getting an idea of where you need to be heading: http://stargazerslounge.com/topic/184192-full-disc-lunar-imaging-with-a-dslr/

James

[blackrat3403]

Thanks for the replies guys.

I'm well aware that the scope is not well thought of, and having used it for the last year or so, i've come to the same conclusion myself. But until I come across some expendable income that the wife and kids don't want i'm stuck with it...

Thanks for your post James, I need to take a good long read through all that. I'll keep trying with the focus and it could've have been a hazy night, can't remember as it was back in February I took the shots.

[Knight of Clear Skies]

As nightfisher says, using zoom on the liveview could help a lot if you haven't already tried it. An image that looks fine on a small LCD screen can actually be quite a bit out of focus. I usually zoom in on the terminator to get it as sharp as possible. I don't think you are that far out, if you can get the focus a bit better a decent image should be within reach if you take a number of frames and stack them.

One tip, you really want the Moon dead centre in your field of view to get the best out of the optics.

I'm a little suspicious of the scope collimation though, as the halo around the Moon isn't symmetrical. Imaging is unforgiving of optics, what looks sharp as postage stamp size in the eyepiece can be pretty rough when blown up to screen size. I've played a little with a Bird-Jones type scope (a Celestron astromaster 114) and this is what I got:

(Heavily cropped but otherwise unprocessed.)

(Full frame. Pretty sharp in the middle - the stack is 5 1/2 miles away so haze reduces the contrast - but shallow depth of field and bad coma apparent. Yet through the eyepiece the image was very sharp.)

Some daytime shots might help you diagnose the issue. Good luck, I hope that is some help.