Imaging with my Evostar 72ED DS-Pro was a fail, any suggestion for me to improve?

[WilliamAstro]

Last night I went to attempt to image the Pleiades but didn't end very well..

I set up my rig which was my 72ED, ZWO Guidescope 30mm F4, a modified Canon 600D with a backfocus tube and 2" adapter, ZWO ASI120MM Mini.

I did polar alignment accurately but I think whilst I was balancing my mount I could have moved the polar alignment off, I think I need to polar align when the telescope is finished being balanced and operated.

Does any of you think I need another counterweight for the mount? When I set the dovetail higher the scope and other stuff would not stay still but I can't go to low otherwise the telescope will be bonked by the mount and my polar scope will be covered.

Guiding did go well but it couldn't help with the error of alignment.

I did 5 minute exposure subs, and I think I should've went with something like 2 minutes..

Upon receiving the lights, all the stars were trails for all images and Pleiades slowly moved away from the camera's FOV.

I used a SWSA 2i for this.

 

Edited October 6, 2022 by WilliamAstro

[rl]

Might help if we could see exactly what was wrong with the subs...can you post one up?

If you carefully slack off the RA you will know straight away if the mount is. balanced or not.

Do you have any evidence that the mount was actually being driven?

[WilliamAstro]

6 minutes ago, rl said:

Might help if we could see exactly what was wrong with the subs...can you post one up?

If you carefully slack off the RA you will know straight away if the mount is. balanced or not.

Do you have any evidence that the mount was actually being driven?

Unfortunately I removed them from my camera as they didn't go well..

Sorry..

But upon viewing the subs, the stars just appear trailed

The mount is being driven and I did set the guiding to RA only.

It did stay in the field of view for a while before moving away.

[bomberbaz]

A pillar sounds like it could come in useful, do you have a picture of your rig set up?

[Elp]

At least youve tried it which is usually how it starts for us all.

You should always polar align after everything is loaded onto the mount and balanced in DEC and RA as any physical contact can push the polar alignment off, especially with a light mount.

You may need another counterweight as I did with my Z61, I never found the SA to be very secure with it on so I didn't use it much, I solved the weight issue by using a longer counterweight bar with the same weight (IE torque), washers and nuts to hold the weight in place, I think from memory its an M10 hole on the SA RA dovetail so I bought a longer all thread bar.

The comment about the polar scope being covered, doesn't the RA dovetail have a cutout running down the centre for clearance for the polar scope?

When imaging you should always preview at different exposure settings and lengths to determine the best settings prior to running a session, there's nothing worse than using up precious hours on a poor session when 10-20 minutes running previews and assessing them can make all the difference. As a very general principle, the longer the focal length of the main scope the more accurate your guiding needs to be.

[WolfieGlos]

On 06/10/2022 at 12:57, WilliamAstro said:

I set up my rig which was my 72ED, ZWO Guidescope 30mm F4, a modified Canon 600D with a backfocus tube and 2" adapter, ZWO ASI120MM Mini.

I did polar alignment accurately but I think whilst I was balancing my mount I could have moved the polar alignment off, I think I need to polar align when the telescope is finished being balanced and operated.

Does any of you think I need another counterweight for the mount? When I set the dovetail higher the scope and other stuff would not stay still but I can't go to low otherwise the telescope will be bonked by the mount and my polar scope will be covered.

Guiding did go well but it couldn't help with the error of alignment.

I did 5 minute exposure subs, and I think I should've went with something like 2 minutes..

Upon receiving the lights, all the stars were trails for all images and Pleiades slowly moved away from the camera's FOV.

I used a SWSA 2i for this.

 

A little late to the party, but I use the same scope, and DSLR and a star adventurer. Attached is a picture of my setup (yes, the camera was upside down!!)

SW 72ED + FF + Canon 77D / 800Da, Baader red-dot sight, ZWO ASI120MM Mini + 30 f/4 guidescope.

This literally **just** balances in RA, with the SA counterweight at the end of the shaft. The only way I can balance it, is putting the guider onto a ballhead at the bottom the SA bracket. If I mount the guider on the scope, it will not balance....short of buying additional weights!

I do not use a longer dovetail for this, just the standard one supplied with the 72ED scope. It even falls just right to enable the red-dot polar illuminator to stay mounted. My weak point is definitely the tripod, it's fine for the weight limit but the legs are a bit flimsy when extended.

Polar alignment is an issue for me as well, particularly with my tripod. What I do now, is polar align in the scope but then I do NOT turn on tracking. What I do next, is locate my target by altering RA and DEC and then note down the marking on the date graduation scale. I then rotate the clutch back to enable polar alignment, then align and turn on the SA. I then carefully rotate back to the same date on the circle.....and voila. It's not perfect, but it's pretty close. I then just check to make sure the polar alignment is still OK.

I generally guide for between 2-4 minutes with no issues, but have done 10 minutes with a 300mm lens.

Edited November 7, 2022 by WolfieGlos

[900SL]

It's likely polar alignment, as the SWSA can only guide about RA.  Plus taking 5 minute subs at that FL and load out, well, good luck with that ..

I also think you are seriously undermounted with all that on a SWSA. Any wind or vibration or slop anywhere will result in duff subs

Edited November 8, 2022 by 900SL

[carastro]

I would agree with that.  I find it difficult to see how your rig can be balanced with that load and that tiny counterweight.

Carole 

[WilliamAstro]

Used the rig again, got this (40-60+ mins) 30 second subs i might still need another counterweight for this though

[WilliamAstro]

speaking of counterweights are their any counterweights for me to obtain? (those tyre looking things)

[900SL]

Looking better on Pleiades Will.

Still some drift looking at the stars. What are you using for polar alignment? 

This is 40* two minute exposures Redcat 51 on Fornax LT, ISO 200. It was breezy.

As a previous owner of a Star Adventurer 2i, I can only speak for my own experiences but I found it to be very frustrating to try longer focal lengths and exposures. Finding targets, tracking, polar alignment drift due to the poor machining, slop in the interfaces, sensitivity to wind, you name it.

It was ok for wide angle shorter exposure, but trying to deal with the SWSA inherent deficiencies in quality and capability meant I ended up throwing money and time at it in an effort to deal with the issues, and was delighted on the day I sold it.

Stick to a lighter load out, balance slightly heavy to one side to ensure positive worm engagement, use shorter exposures, and get a good PA routine using AAP if you are using that, or collimate the Polarscope

Edited November 9, 2022 by 900SL