First Prime Focus Image

wmzaphod · #1 22-05-2008, 08:12 PM

Hi Guys,

My first attempt - not exactly what I expected but a start......tips and advice welcome (please).

http://farm3.static.flickr.com/2286/...e663ec16_b.jpg

Skywatcher 80mm refractor, Canon 20D, 24x10sec exposures, stacked in RegiStax and the slack newb I am, I can't remember which part of the sky I photographed

.

Link to the full sized image

Bassnut (Fred) · #2 22-05-2008, 08:18 PM

Hi Peter

umm, 10 sec exposures?. Thats a bit short, well for anything really, cant see anything there but dodgy stars. Its hard to evaluate anything based on this. Sorry, go longer dude.

wmzaphod · #3 22-05-2008, 08:23 PM

Quote:

Originally Posted by Bassnut

Hi Peter

umm, 10 sec exposures?. Thats a bit short, well for anything really, cant see anything there but dodgy stars. Its hard to evaluate anything based on this. Sorry, go longer dude.

Hi Bassnut, I started with longer but was getting trails (still haven't got the scope tracking right yet). What's your recommended exposure time?

Cheers,

Peter

iceman (Mike) · #4 22-05-2008, 08:27 PM

Hi Peter

Links aren't working for me.

First step is to get the mount tracking right - that's the #1 priority. You have to learn how to polar align and drift align.

Then you can do 30s or 1 minute exposures until you get guiding working.

Bassnut (Fred) · #5 22-05-2008, 08:32 PM

Hi Peter

Well, if you have tracking problems at 10 secs, you really MUST polar align better 1st. Whilst polar aligning, aim for 5mins without the star moving too much. You really need to do this 1st. Guiding will help, but good polar align is a critical 1st step. Then, with only tracking, you can take reasonable 30 sec subs (actually, you could go longer with the short FL ED80/DSLR combo). Very quickly after that, you will need to add guiding to get typical 5 min killer exposures.

wmzaphod · #6 22-05-2008, 08:35 PM

Quote:

Originally Posted by iceman

Hi Peter

Links aren't working for me.

First step is to get the mount tracking right - that's the #1 priority. You have to learn how to polar align and drift align.

Then you can do 30s or 1 minute exposures until you get guiding working.

Yeah, I know... had it tracking quite well last week and got a 71 sec exposure with just about no movement. I'm just not consistent with setting it up yet.

I've also been told to take lots of short exposures and stack rather than long ones - I'm confused (quite common)

Try this link flickr - should work ok.

wmzaphod · #7 22-05-2008, 08:37 PM

Quote:

Originally Posted by Bassnut

Hi Peter

Well, if you have tracking problems at 10 secs, you really MUST polar align better 1st. Whilst polar aligning, aim for 5mins without the star moving too much. You really need to do this 1st. Guiding will help, but good polar align is a critical 1st step. Then, with only tracking, you can take reasonable 30 sec subs (actually, you could go longer with the short FL ED80/DSLR combo). Very quickly after that, you will need to add guiding to get typical 5 min killer exposures.

Ahhh, so I'll still need an auto guider for the long stuff, makes sense

edwardsdj (Doug) · #8 22-05-2008, 08:49 PM

Quote:

Originally Posted by wmzaphod

I've also been told to take lots of short exposures and stack rather than long ones - I'm confused (quite common)

For planetary imaging hundreds to thousands of short exposures work best. This is because most planets are bright and the magnification required is huge. This is why people capture video sequences for planetary work.

For deep space (which is what you are attempting here) you need long exposures and consequently good tracking.

Bassnut (Fred) · #9 22-05-2008, 08:57 PM

well, its a balance bettween longer exposures and stacking. To do good imaging with a DSLR, really, stack 5 min exposures (in urban skies), the more the better, thats the go. Anything much less than 5 min subs for DS is just temporary progress. Stacking really short subs is just hard work, you need to overcome read noise with longer exposures. I see many ppl making tiresome incremental improvements with short exposure times/huge stacking and just tracking, get the fundamentals right (polar align and guiding, do it now, dont waste time) and youll be supprised at the results.

Bassnut (Fred) · #10 22-05-2008, 08:59 PM

Doug

The man has a DSLR/ED80, hardly the set up for Planetary?

wmzaphod · #11 22-05-2008, 09:29 PM

Quote:

Originally Posted by edwardsdj

For planetary imaging hundreds to thousands of short exposures work best. This is because most planets are bright and the magnification required is huge. This is why people capture video sequences for planetary work.

For deep space (which is what you are attempting here) you need long exposures and consequently good tracking.

Right, I understand that now

Quote:

Originally Posted by Bassnut

well, its a balance bettween longer exposures and stacking. To do good imaging with a DSLR, really, stack 5 min exposures (in urban skies), the more the better, thats the go. Anything much less than 5 min subs for DS is just temporary progress. Stacking really short subs is just hard work, you need to overcome read noise with longer exposures. I see many ppl making tiresome incremental improvements with short exposure times/huge stacking and just tracking, get the fundamentals right (polar align and guiding, do it now, dont waste time) and youll be supprised at the results.

I will. Promise not to post again till I have the tracking right.

Quote:

Originally Posted by Bassnut

Doug

The man has a DSLR/ED80, hardly the set up for Planetary?

That's right, not aiming for planetary yet

Thanks for all your help guys.......

Peter

edwardsdj (Doug) · #12 23-05-2008, 03:53 AM

Quote:

Originally Posted by wmzaphod

I will. Promise not to post again till I have the tracking right.

Please don't stop posting!!!!