My first attempt at astrophotography with only a DSLR

[imakebeer]

@FunkyKoval35 @carastro

I think there's a danger (and it's by no means restricted to you, this thread of even this forum) in discouraging newcomers by telling them that they must have this gear or that gear - the inference is that there's no point even trying unless you have some mega-expensive setup, which is a real shame as it's demonstrably not true and there's still a lot of fun to be had even with basic equipment.

Are tracking mounts and guiding good? Absolutely.

Are longer exposures better? At reducing read noise, yes, but bear in mind there are also other sources of noise to contend with. Some of these can be mitigated by stacking multiple images, hence my argument for the importance of total integration time rather than individual exposure length.

1 hour ago, carastro said:

You cannot get decent DSLR images with short exposures, getting lots of them will only give less noise, not increase the signal captured.

This doesn't make sense. Firstly the definition of a long or short exposure is totally arbitrary. Secondly the greater the total integration time (however you do it) the more photons can hit the sensor hence total signal must also be increased, no?

My advice for the OP is simply not to be discouraged if you don't yet have all the gear one might desire, but rather to work with what you've got and above all have fun! The flip side is you need to keep your expectations in check and understand that there are good technical reasons why your images might be noisier than others you see - accept these limitations and work within them. Along the way there are plenty of valuable lessons to be learned on the post-processing side (e.g. when working with limited/noisy data don't get greedy with the histogram stretch!) which will stand you in good stead as and when you're able to upgrade.

[FunkyKoval35]

3 hours ago, imakebeer said:

I think there's a danger (and it's by no means restricted to you, this thread of even this forum) in discouraging newcomers by telling them that they must have this gear or that gear - the inference is that there's no point even trying unless you have some mega-expensive setup, which is a real shame as it's demonstrably not true and there's still a lot of fun to be had even with basic equipment.

First of all.. I never mentioned that people MUST have this gear or that gear... Of course, everyone has equipment they can afford or want to have. I only claimed in my comment that you are givin wrong assumption/information that it does not really matter if we do multiple short exposures or one long exposure.

3 hours ago, imakebeer said:

This doesn't make sense. Firstly the definition of a long or short exposure is totally arbitrary. Secondly the greater the total integration time (however you do it) the more photons can hit the sensor hence total signal must also be increased, no?

It is not about signal itself... When you do shorter exposures you have lower SNR - Signal to Noise Ratio.

http://dslr-astrophotography.com/long-exposures-multiple-shorter-exposures/

 

Edited June 9, 2023 by FunkyKoval35

[carastro]

Absolutely, I was just saying what would be ideal, but also what is the minimum the OP needs to improve his images.

@imakebeer since you quote? 

Quote

I'm still new to AP only having started in Oct 2022 so feel free to take this with a large pinch of salt,

I don't really think you are in a position to criticise advice given by those with years of experience.   DSLRs do not work in the same way as CMOS, i.e. lots of short images but lots of of integration time will get you great images.  As Funkykoval demonstrates in his excellent  image examples of different length exposures but same total imaging time.  

Quote

 

Edited June 10, 2023 by carastro

[carastro]

I shall now stay off this thread, the original poster can choose what advice he wants to take and what he can afford.  If he wants further advice he is welcome to PM me.

[DaveS]

The OP should take very much note of what Carole has to say, she's been doing AP for longer than most here, including with DSLRs and her images have won awards on other fora.

M101 is a very difficult target, especially under suboptimal conditions. If you want to keep on without a tracking mount due to financial restrictions then wide angle images of bright targets is the way to go.

This might be about the cheapest tracking mount available.

https://www.firstlightoptics.com/equatorial-astronomy-mounts/omegon-minitrack-lx-quattro-ns.html

 

[ApophisAstros]

On 05/06/2023 at 12:32, carastro said:

M101 is very faint, and 2secs won't cut it, especially from a Bortle 7 - 8 location.  You might be able to get some of the brighter targets but tracking, guiding and long exposure is really needed for DSOs.    

The good news is that your stars are nicely in focus, and you have done the right thing with calibration (especially flats) and lots of subs.  

A but of post processing would bring it out a bit more:

Great advice Carole having started with DSLRs myself ,

Roger

[ApophisAstros]

17 hours ago, imakebeer said:

@FunkyKoval35 @carastro

I think there's a danger (and it's by no means restricted to you, this thread of even this forum) in discouraging newcomers by telling them that they must have this gear or that gear - the inference is that there's no point even trying unless you have some mega-expensive setup, which is a real shame as it's demonstrably not true and there's still a lot of fun to be had even with basic equipment.

Are tracking mounts and guiding good? Absolutely.

Are longer exposures better? At reducing read noise, yes, but bear in mind there are also other sources of noise to contend with. Some of these can be mitigated by stacking multiple images, hence my argument for the importance of total integration time rather than individual exposure length.

This doesn't make sense. Firstly the definition of a long or short exposure is totally arbitrary. Secondly the greater the total integration time (however you do it) the more photons can hit the sensor hence total signal must also be increased, no?

My advice for the OP is simply not to be discouraged if you don't yet have all the gear one might desire, but rather to work with what you've got and above all have fun! The flip side is you need to keep your expectations in check and understand that there are good technical reasons why your images might be noisier than others you see - accept these limitations and work within them. Along the way there are plenty of valuable lessons to be learned on the post-processing side (e.g. when working with limited/noisy data don't get greedy with the histogram stretch!) which will stand you in good stead as and when you're able to upgrade.

I am not sure that it’s for third parties to control the advice given as it’s from experienced imagers who have been there and done it. I would just say that it always know youkits limitations as it’s easy to get frustrated and perhaps not stay in a wonderful time travelling adventure with the bonus of beautiful images.

Good Luck for future endeavours 

Charming Potato👍😄

Edited June 10, 2023 by ApophisAstros

[david_taurus83]

Just to point out, DSLR's themselves have CMOS sensors and they work almost exactly like dedicated astro CMOS, the catch being they are not as efficient. Where modern astro sensors QE (quantum efficiency) range is anywhere between 60/90%, a Mark I Canon 6D, probably the best DSLR for astro work, its QE range is only around 46/49%. So if you pit it against the well regarded IMX571 sensor, you would need to gather almost twice as much exposure time with a 6D as you would with a 571 type camera. Short exposures will work with a DSLR but you would at least need to expose above the noise level and have many, many subs which would require large storage space and lots of processing power to stack them which makes it impractical in reality. 

[teoria_del_big_bang]

On 10/06/2023 at 10:42, DaveS said:

The OP should take very much note of what Carole has to say, she's been doing AP for longer than most here, including with DSLRs and her images have won awards on other fora.

I can only reenforce that comment. Carole has taken many great images, and without a lot of the bells and whistles, so for sure knows what whe is talking about. I had some exceptional advice from her when I first started and will be forever grateful (she saved me a lot of wasted cash 🙂 , which for a Yorkshire man is top priority)

Steve

Edited June 18, 2023 by teoria_del_big_bang

[wesdon1]

On 06/06/2023 at 15:41, Charming Potato said:

I am trying to look into used EQ mounts, but I haven't been able to find anything used so far for a good price (or something good in my range). I want to get something that will last me a good while as I want to get some sort of telescope or lens designed for astrophotography later on, so maybe something that can handle a good amount of weight? I've been trying to look for a EQ5 mount as you suggested in my other post earlier this week.

 

So I used the NPF rule for calculating this; one online and one in Photopills app. And both of them gave me exposure time of about 2-2.5 according to 100mm lens and that is what I rounded down to 2. I do have another lens which is 15-50mm @ 3.5-6.3 aperture, and this lens' lowest focal point is at 50mm at 4.5 aperture. I'll try both of them next time and see how it goes. Thank you for the suggestion!

 

I have also did the post processing again for the image, did I do it too much this time? I have played around with levels and curves, and added a little bit of saturation.

@Charming Potato Hi again, I'm so so sorry for such late reply, I have had a bad time with a family emergency. 

I have never used the NPF formula, tbh, so I can't tell you whether it's better or worse than the 500 formula I suggested. I do however know that NPF is more complex than the 500 formula, something to bare in mind.

As for you picture, it's awesome considering you're so early into the hobby. Maybe try adjusting the sats, levels and curves a little more to "force out" more colour and contrast? Obviously you can't "force out" colours/details that simply aren't there, so it will depend on how much exposure/integration you managed overall. Just keep playing around with processing, imaging etc and have fun, and you will naturally get better with time. I learned the hard way that this hobby doesn't allow "short cuts" so to speak, it just takes time and persistence.

Finally, I'd suggest you mostly listen to the very experienced vets on here, as they have been doing this for years and know all the best tricks of the trade. I wish you every success, and will follow your progress!

Clear Skies, Wes.