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Astrophotography


Mercona
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I'm not sure if it's just the city lights or what. But I can't even come close to taking a decent picture of deep space objects. I've seen dozens of backyard pictures of galaxies with amazing detail. I'm using a Meade 2120 10" ls5 with a lodestar and an Orion shortube90 for guide scope. I have a bresser exos2 that I regressed and fine tuned the gears a bit. It's stable, very little backlash. I can use my BT mask to get near perfect focus but all my pictures are either washed out or just stars. The picture attatched is the best I've gotten from backyard photos. It's m101 Any help would be appreciated. 

image.jpeg

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I'm using a Canon t5i. This picture was 50 second exposures. I think 25 pictures. I tried longer but the image background just washes out the image. This native f10? That isn't something I've heard. I thought the shorter the f stop the less exposure time for same result 

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I just ordered one yesterday. I read mixed reviews on filters. 50% say yes they are amazing and 50% say save your money. Should I get a reducer/field flattener? 

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It does depend on the type of LP and which filter you get.

The best imo are the Astronomik CLS clip filter, I use this one.

The other is the Hutech IDAS P2 or D1.

I have a mixture of LP here, mercury and sodium plus other lighting.
The Astronomik deals with all these and with my setup I can easily do 5minutes at f4.

To give you an idea I can just see some of the milky way on a good night.
Here is my local LP about 8 streetlights within 100yards, you can just see the Plough, Big Dipper over your side. :icon_biggrin:

streetlights.jpg

 

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Re the reducer.

Personally I would say yes but I don't know your scope and how well it does with one.

For DSOs and a DSLR  I would go as fast as possible, one thing, do expose correctly whatever your setup.
 

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To give you an idea how well some LP filters do.

To the left in the above photo is our local football club, this has 6 very powerful floodlights.

Here is a test I did when M27 was in the full glare of these lights.
These were 2minute exposures with a Canon 60Da and a 200mm lens, with the Astronomik clip filter.

m27.jpg

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Yeah, I'm sure it's the same lghting. I live near a small airport, and hospital. By near I mean about 1-2 miles. Both seem to light up the sky pretty good. Enough that when I'm in my back yard I can see tree tops glowing from the light. I know I can do a 45 sec exposure of my back yard and it looks like it was taken on a sunny day. I'm hoping this filter will work. I've seen some amazing pictures from people living in a much more light polluted city. Thanks for the help. I've used both my scopes with same results. The other is a Astro-tech RC6 but I believe it's an f9. 

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What does the histogram look like on one of the single exposures on m101.

Most images members share are made from many separate images that are then stacked, so a single image is never the final detail and probably doesn't look much.

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Yeah, I'm sure it's the same lghting. I live near a small airport, and hospital. By near I mean about 1-2 miles. Both seem to light up the sky pretty good. Enough that when I'm in my back yard I can see tree tops glowing from the light. I know I can do a 45 sec exposure of my back yard and it looks like it was taken on a sunny day. I'm hoping this filter will work. I've seen some amazing pictures from people living in a much more light polluted city. Thanks for the help. I've used both my scopes with same results. The other is a Astro-tech RC6 but I believe it's an f9. I'm not sure what the histogram looks like. 

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10 hours ago, wxsatuser said:

To give you an idea how well some LP filters do.

To the left in the above photo is our local football club, this has 6 very powerful floodlights.

Here is a test I did when M27 was in the full glare of these lights.
These were 2minute exposures with a Canon 60Da and a 200mm lens, with the Astronomik clip filter.

m27.jpg

If that's not proof of how powerful a light pollution is I don't know what is.

Nice one

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  • 2 weeks later...

Well I finally got a clear night to use the filter. No such luck with any better pictures. In fact it's not much improvement over not using a filter. Ugh. This is sooo.. frustrating

 

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You wont get any improvement until you get that reducer installed. If youre going from f10 to f6, thats a massive leap forward in terms of photographic speed. Those 50s exposures you were doing at f10 will be worth 135s at f6. And, becuase you have reduced your focal length you will be able to guide for longer (or more realiably) - which is important since in order to get better images, you need to expose for longer.... which is where the LP filter comes into play becuase the longer you expose, the more LP you are capturing (so the filter helps keep that to a minimum).

However.... for someone getting into AP... a Meade 10" isnt going to make life easy. In fact its probably one of the hardest to learn on - barring ultra-fast systems of f4 and below.

When I first started... I clearly remember thinking "well how hard can it be?!".... the answer was "actually... quite hard!" (for the first couple of years).

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I'd definately start with an M13, M3 or M27.

M27 is a good, bright, fairly large target which would be a great starting point for practicing.

I'm just blatently copying ollys post aren't I?

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OK. Hopefully it will be clear skies tonight. Last night I did a 5 min exposure at iso 800 and it didn't come out very good either. I was waiting for an attachment piece to connect my reducer to my camera. As of now I have scope, filter, dual speed focuser and camera in that order with no way of really attaching the reducer without about 4-5 inches before reaching the sensor. Should I set it up as scope, focuser,reducer,filter then camera? Thanks again for all the advice

 

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33 minutes ago, Mercona said:

OK. Hopefully it will be clear skies tonight. Last night I did a 5 min exposure at iso 800 and it didn't come out very good either. I was waiting for an attachment piece to connect my reducer to my camera. As of now I have scope, filter, dual speed focuser and camera in that order with no way of really attaching the reducer without about 4-5 inches before reaching the sensor. Should I set it up as scope, focuser,reducer,filter then camera? Thanks again for all the advice

 

Yep thats how it normally goes, scope>reducer>filter>camera. Apart from 2" filters, which are quite often used on the the scope side of the reducer (many reducers or flatteners have 2" filter threads scopeside).

The main thing to watch for is your spacing, as once you get a reducer in the optical train - incorrect spacing can lead to distortions in the corners of your images. Additionally, the reducer might not cover APS (or larger) chips so its a case of "suck it and see". Its probably a good idea to go hunting for images taken with that exact setup so you know what to expect.

Get yourself one of these.... worth its weight in gold when youre working on your spacings:

49_923_150.jpg

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6 hours ago, Mercona said:

OK. Hopefully it will be clear skies tonight. Last night I did a 5 min exposure at iso 800 and it didn't come out very good either. I was waiting for an attachment piece to connect my reducer to my camera. As of now I have scope, filter, dual speed focuser and camera in that order with no way of really attaching the reducer without about 4-5 inches before reaching the sensor. Should I set it up as scope, focuser,reducer,filter then camera? Thanks again for all the advice

 

You might think a single exposure looks awful but in reality a few stacked and processed will bring out all sorts of detail.

Here is a single 5minute exposure of the California Nebula, this was at f2.8 105mm focal length.
The RAW was converted to TIF in Camera RAW  but for this purpose it shows you that very little detail is apparent.
The second image is 25 of these images stacked and processed, as you see a lot goes on in processing.

caltest.jpg

calitest1.jpg

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Yes I need to find a new computer to stack with I have an iMac that's super powerful but all the really good stacking programs cost a ton of money. I have another computer that's not a Mac that I downloaded some free stacking deep sky stacker but it kept crashing my computer. Here are a couple I did last night they were both probably 3 and a half minute exposures single shots

Screenshot_2016-07-17-08-29-41-1-1.png

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Make sure you do not have Drizzle enabled in DSS, as this will no doubt cause it to stop, unless you have a shed load of memory.

Your in the same boat image wise as your still imaging at f/9, this is still slow.

Be interested to know, what the in camera histogram looked like.
Where was the peak of the histogram as this will give you the correct exposure.
You will have a correct exposure when the peak is somewhere between 25 to 40% on the Canon histogram.

Like this, look at the white luminance histogram

info.jpg

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