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Uranium235

First Light w/ 1000d (M81 & M3)

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Just finished stacking last nights results and in conclusion, the Canon 1000d knocks the socks off the Nikon D60 when it comes to taking long exposure subs. Focusing was a breeze with live view over USB, and the control software is fantastic too (set up & walk away). No sign of the volcanic ash cloud either (yet).

I managed to get remote assistance up and running too so I could watch it all from the basement :D In the end though the guidescope kept dewing up every 5 min so PHD lost tracking (something like 3am that was). Despite some polar alignment problems that took a while to fix, i managed to get 45 min on M82 (I cropped out M81) and M3 AND get some proper darks and flats done (at sunset). Proper darks & flats are worth the hassle.

Canon Rules..... Nikon Drools! :)

15x180 sec Light, 10x180sec Dark, 10 Flat, 10 Bias

post-18171-133877440886_thumb.jpg

post-18171-133877440893_thumb.jpg

Edited by Uranium235

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Nice pictures! I have just bought a Canon 1000D and looking forward to using it for Astrophotography! Never attempted it before but the more I see pics like this using the entry level camera it certainly is encouraging to give it a try. I take it the camera is not modified? Do you have plans to do this for better H-alpha sensitivity?

Brendan

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Just finished stacking last nights results and in conclusion, the Canon 1000d knocks the socks off the Nikon D60 when it comes to taking long exposure subs. Focusing was a breeze with live view over USB, and the control software is fantastic too (set up & walk away).

Canon Rules..... Nikon Drools! :D

Nice work... I'd like to say I told you so....

Peter...

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Very nice shots. How long were the subs? I continue to have real problems tracking with PHD (either diff. flex. or operator errors) and usually get some trailing after about 4-5 mins with my Canon 400D at Prime focus.

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Nice work... I'd like to say I told you so....

Peter...

Thanks Peter! Looks like im eating humble pie for Sunday lunch...lol... :D

Lukebl, im using 15x3min subs for both of them - with 10x3min darks too. I didnt want to push the exposure length too far given the dec problems ive had recently (less wasted subs). I can understand the hassle youre having, mine was eventually solved by polar-aligning twice and finding a better guide star (wish id done that at the start of the session!).

The camera is new and straight out of the box (unmodded), its unlikely its ever going to see a real camera lens so Im mulling over whether to have it modded or not. Which leads to to a question, if I had it astronomized is it better to have a filter change, or the filter removed totally?

Edited by Uranium235

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Incidentally, do you use the default PHD settings, or have you adjusted them? Just finding out how to improve my own imaging success.

Best wishes,

Luke

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In PHD:

RA Agressiveness = 105

Hysteresis = 50

Dec guide mode = Auto

Max dec duration = 300

Calibration step = 1000

Exposure time 0.5 - 2sec (depending on availablility of good guide stars)

On mount:

Anti-Backlash RA and DEC = 0

You can try that (the settings i used last night), but if youre still having problems after that it could be something do do with either your choice of guidestar, polar alignment or balance... or all of the above!

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Might give those settings a try.

My RA Hysteris is set for only 10, and Dec duration of 150ms, but I've never really understood what they mean anyway despite reading the definitions over and over.

Here's a single frame, with an enlargement showing the blobby stars in a 6 min exposure:

IMG_7227_copy.jpg

Sorry, don't mean to hijack this thread or anything! Just always trying to find a solution.

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Wow... you should have got more for 6 min :) what target is it BTW? And what scope are you using? ISO setting on cam?

Are your tracking problems coming in RA or DEC? The hysteresis is used to average out RA tracking to stop sudden changes, the higher it is - the smoother it is. The max setting is 50.

But like I said earlier, choice of guidestar and polar alignment are just as important (if not more) than messing with the PHD settings. Use the star profile window to choose one that shows as a sharp spike which isnt bloated, if you have adjusable guidescope rings (very handy) you can choose the best star on screen and move it to the bullseye area before performing PHD calibation.

Dont worry, plenty of time for practice next week cos there is going to be a lot of clear sky and fair weather (wed-fri hopefully) :D

Addition: Just a thought - If youre having problems with one target, try another spot in the sky and see if the problems go away or reduce - try not to sit there getting really angry (like I do...lol). I had a problem getting M101 once, so I just slewed round to M3, tried again and it was perfect (that told me it was a balance problem).

Edited by Uranium235

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ISO 800, 200mm f/5 Newtonian, guided with a ST80. Guide star brightness wasn't a problem, and it stayed nicely in the cross-hairs and the phd graph looked good. I also know that coma is an inherent issue with this scope, which you can see clearly away from the centre of the image. It's a fairly sparse star field, so I wouldn't expect to see many stars anyway. Nevertheless, there are stars down to mag 17.5 in the image, so I don't think magnitude limit is a problem. Here's the finished result:

ngc4302b.jpg

It's NGC 4302 and 4298, in Coma Berenices by the way. Interesting pair of galaxies, but I realise a bit too small and dim for my equipment. A bit disappointing after two and a half hours of imaging, but we live and learn! Put it down to differential flexure.

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Ahhh, youve got a big scope then :D Your ISO is right and your graphs are ok.. hmmmm... maybe youre right in that you may have reached the limit at your current location (if you live in an LP area) or flex is coming into play.

I try not to worry about coma tho, I get the same from my newt and its easily removed by cropping the image to the area of interest. Not unless you want to fork out £120 for a coma corrector, which would come in handy if youre going for a big target.

Did you take any flats? That would make a noticeable difference to the end product.

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Yes, I did take some flats. Although never really found that makes a huge difference, apart from evening out the background.

Will persevere. Onward and upward, and other such clichés!

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If you go the filter removed route you open up full spectrum imaging... if your using any "glass" in the imaging train you will want to limit the UV and IR when doing the Visible and Ha...

One of my cams is full sprectrum (filter removed) and the other is BCF equipped...

I use Astronomik CLS-CCD and Idas P2 filters both of which take care of the UV/IR cut for me...

The other think to watch is if your ever going to use a normal camera lens on a filter removed camera you need to reshim the image sensor to be able to get infinity focus...

I didnt bother doing this with the 350D and regret it...

Peter...

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Thanks Peter, I was thinkin about that again earlier becuase I was taking a look at the cone nebula and thinking whether an unmodded 1000d will pick that up or if I needed to have it removed to do any kind of H alpha work.

Also need a list of interesting targets that the 1000d will happily do without modding, so I will work on that a bit later.

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