IamLost

Using my Evostar ED80 pro and a canon 700d with no guiding, I managed to get my first complete DSO.

182x30” subs at ISO 1600

15 flats

15 darks

20 bias/offset

stacked in DSS

edited on PixInsight 

total exposure time of ~ 1 hour 30 minutes

There is quite a lot of noise and some of the large stars have trailing due to imperfect polar alignment, but overall I was glad with how it turned out.

611C6392-0F43-472C-B74F-B8CE80984379.tiff

24 minutes ago, FaDG said:

Mmmh, don't know, never happened to me with my 650d. Is it the first time you experience this? 

You could try to shoot the biases again and check their size. If still ABnormal, then try shooting 1/2000th instead of 1/4000th and see what happens . 

Alright I will try that. Thanks for the help

12 minutes ago, FaDG said:

Hi there, you're not telling much about your rig, especially camera. 

Just trying to guess : maybe - if using a DSLR - you selected JPGs for the Bias and RAWs for the rest? Or you shot at a different quality setting? 

The camera I’m using is a Canon 700D. I definitely used RAW for all images I took and kept the image quality the same so I have no idea why the file is a different size

Yesterday when I went to stack my images after a long session, I got an error message from DSS saying that some of the files were incompatible due to size or colour channel. I looked at all of them and the only different files were the bias frames which had a different colour Channel and a smaller image width and height for some reason. I unchecked the bias files and the processing worked so I was wondering why I couldn’t use the bias files and how to use them like I had done so previously without doing anything differently.

On 29/03/2020 at 10:38, Grotemobile said:

What I do is a planetary align . U have got Venus in the sky @ the moment .

That is what I have used. U can use the moon as well.    

Ok thanks

On 28/03/2020 at 19:13, david_taurus83 said:

Drift aligning requires a guide scope and camera connected to PHD. I'm guessing if your asking your at the beginner stage so drift aligning might be a bit advanced. What mount do you have? If a Skywatcher or Celestron then the handsets should have a polar align feature that doesnt require you to even see Polaris.

I have an EQ5 Mount with an RA motor drive so it doesn’t automatically allign

15 hours ago, michael8554 said:

Yes. Setup mechanically aligned as best as possible to North Celestial Pole

Then swing round to near South and the celestial equator and then Drift Align with a high power eyepiece, which ideally has a reticle. 

Or if you're guiding with PHD2 then use their Drift Align method. 

Michael 

Ok thanks for letting me know. What is drift alignment exactly? I’ve read a bit about it but I don’t fully understand it.

Basically Polaris is blocked by my house so I cannot use it to align and I was wondering whether or not there is a way to align without seeing Polaris. I’d like to do some imaging so it would have to be aligned well enough that there won’t be noticeable trails. Thanks!

19 hours ago, Cornelius Varley said:

The EQ5 RA motor is rated at 6v only. A suitable 6v psu or a 6v rechargeable lead/acid battery is required.

Thanks for the help

13 hours ago, DaveL59 said:

did it not come with a battery box and controller?

The EQ2 clock drive (simple version) the battery went in the motor box but the clockwork drive one I have came with the above. Isn't the EQ5 one similar, or is it just you're added a motor only?

I’m not sure because it hasn’t been delivered yet but it may come with a battery box. Do you know what kind of batteries I will need to power it?

What is the best thing I can use to power my EQ5 RA motor and what kind of supply do I need (what voltage and current)? Also, would a normal laptop charger work as long as it has the correct output? Thanks.

33 minutes ago, vlaiv said:

Depends on what you mean by detail.

If you mean signal or what we call depth - that is rather controversial topic - I'll will put forward my view on it:

- short exposure has as much signal as long exposure, even single short exposure - this is controversial part as many people will disagree with me on this one

- short exposure has much more noise.

- Signal to noise ratio is important for what we call depth of the image. Difference between many short exposures and few long exposures - all adding up to same total time is in read noise of the camera - everything else is the same. If one had 0 read noise camera - there would be no difference between the two (many short vs few long).

Since there is no such thing as camera without read noise - fewer long subs always win in terms of SNR over many short subs - but it does not always win by same "amount". If read noise term is small compared to other noise sources - and that happens when light pollution is very strong (LP noise) or target is very bright (target shot noise) or camera does not have cooling and is running hot - thermal noise. In all of these circumstances there will be very small difference between many short subs and few long subs.

If you have cooled camera and dark skies and going for faint target, then read noise is not negligible and there will be quite a bit of a difference between short subs and long subs.

But there is another meaning to detail - actual resolution or detail captured and here we can argue that more short subs have better detail than few long subs.

Again things are not as simple as that but we have two important factors to consider when we talk about level of detail - atmosphere and mount precision. Both reduce level of detail (in terms of sharpness) of the image, and here shorter subs have advantage because they don't accumulate as much of a blur as long sub. Of course, that depends on atmosphere and mount and respective exposures, but yes - there is a technique called lucky DSO imaging that exploits this and uses many, many very short images - like 0.5s images and tens of thousands of such to produce very good sharp images of DSO objects.

For example this:

This image is made out of 2000 one second exposures with dobsonian telescope mounted on EQ platform

Have a look at more images from Emil here:

http://www.astrokraai.nl/viewimages.php?t=y&category=7

(btw, that is author of planetary stacking software AS2/3!).

Thanks a lot for the info  I didn’t know you could take images like that with only 1 second exposures!

7 minutes ago, carastro said:

Definitely, why don't you give it a try?

The reason why I’m asking is because I can’t really take any exposures longer than 0.5 seconds because I don’t have an RA motor drive yet, but when I get one I will compare them.

Basically, I was wondering if there would be a difference in detail between, for example, one 15 minute exposure and 1800 0.5 second exposures.

17 minutes ago, michael8554 said:

With your present setup take a series of exposures from 5 seconds upwards (without manually trying to track), say 5, 10, 15secs, and examine the results.

Then you will know the exposure that gives acceptable trailing.

You don't need to take photos of your screen, use the Prt Scrn button on the top row of your keyboard to send a screen grab to the Clipboard.

Thanks for the advice, and also the reason I took a photo of my screen was because my login details for this site are saved on my phone so I posted this on my phone 

3 hours ago, happy-kat said:

Unfortunately in a catch 22 situation. If you are manually tracking I would reduce your exposure length down to say 5 seconds but this means now needing to capture many more images to then stack to combine what you captured.

Orion is a large target in this case I would actually use just your camera and a camera lens, if you have the kit lens use that. You could even try 20 seconds or even 30 if at 18mm and try hand tracking again.

I’ll probably just get some motors but thanks for the info

1 hour ago, ollypenrice said:

You need an accurate, motorized mount for this job. That's my honest answer.

Olly

Ok Thanks

25 minutes ago, dobblob said:

Which Skywatcher EQ 5 mount are we talking of here? Which brand? The EQ 5's I see out there are the costly goto's and do not have a manual cable.

If yours has a manual cable to turn RA then it is certainly a mount unsuitable for astrophotography on nebulae. Also you say it is not motorised ?

Best post a photo so we are sure what you have.

Edit: Sorry, I see which one you have now-indeed a manual EQ. So yes it is very difficult to track manually no matter how smooth and steady you feel your control is. Also as soon as you touch the cable handle it will impart movement and vibration into the scope. Those cables are really only intended for manual steering.

How are you looking at the star/image to perform the manual tracking? Usually the camera will not show a live view so I can only guess you have a second scope attached or using  a finder.

Yes, I was looking at the stars by using a finderscope and the thing I was using to manually turn the telescope was this https://www.harrisontelescopes.co.uk/acatalog/skywatcher-slow-motion-cable-set-eq2-eq5-az3.html?gclid=EAIaIQobChMIm7aOuYLa5wIVRrDtCh0fyQAYEAQYAiABEgI_rvD_BwE

I recently got a photography setup consisting of an EQ5 mount, ED80 and a canon 700d. For the first time, I tried to photograph the Orion Nebula  but It didn’t go too well. The actual nebula itself was distinguishable, however since I was using the manual slow turn cable to account for the earth’s rotation I found it extremely difficult to actually get a photo without any stars trailing. Are there any ways to reduce this or do a better job manually, or am I going to have to get some motors for the mount? I’ll include the image I took with a 20 second exposure (it’s slightly blurry and cropped because I took a photo of my computer screen)

19 minutes ago, fozzybear said:

are you sure the camera adapter is m48 as should fit ?

Yeah the m48 fits into the camera but idk what part of the telescope to connect it to

6 minutes ago, Anakin Skywalker said:

I had the same issues when i first bought my Nikon D3500 for astrophotography. I had no idea how to connect the DSLR to my Nexstar 6SE so i watched a few Youtube videos of how to do it and i found two ways to attach the camera. 

1. Attach the T-ring to the camera and attach the Barlow lens onto it by screwingit into the T-ring (using its built in ridges) and inserting it into the star diagonal on the  telescope like a normal lens.

2. Attach the DSLR and T-adaptor directly onto the back of the telescope body using the tube of the telescope as a giant lens for the camera

try watching this

 

Thanks for the info

4 minutes ago, fozzybear said:

I think don't own an ed80 the M48 attaches directly to the drawtube on the focuser did you buy the scope new? as in the box if you bought the scope with all accessories finder diag etc etc There is also a 2” T ring camera adapter and a short extension tube. yes or no? then you can attach filters to that or buy an 1.25 adaptor like this

https://www.firstlightoptics.com/adapters/astro-essentials-1-25-inch-t-mount-camera-nosepiece-adapter.html

Yes I bought it new. The box didn’t contain a 2” ring but there was a smaller T-adapter tube thing but it doesn’t fit my m48

I recently bought an m48 t ring to connect my canon camera to my telescope, but don’t know what to connect the other end of the ring to. Also, how would I attach a 1.25” filter to the setup as well. The telescope I have is a skywatcher ed80. Thanks.

39 minutes ago, wimvb said:

The T-ring should have a bayonet connector that fits on the body of the canon, without any lenses attached. The other side of the ring screws into the field flattener of your scope. 

The T-ring should look like this 

https://www.firstlightoptics.com/adapters/skywatcher-dslr-m48-ring-adapter.html

Sorry I got it wrong. I checked the part and it said T-adapter. Is that the part that I connect to the m48 ring?

I recently bought a skywatcher ED80 and was wondering how I can connect it to my canon 750d (I.e. what accessories do i need). The telescope came with this thing that said T ring but i can’t see how it’ll attach to the camera. Also, would I be able to connect a Barlow and a 1.25” filter to it? Thanks for any help.