Spaced Out

If you've got a mount capable of astrophotography with a 200p and you're used to using newts (collimation etc) then the 130 PDS seems a reasonable choice. Coma corrector will be required too for decent stars right to the edge, of course a CC could always come later tho. I liked my 130 PDS so much I bought two in the end !

I had an ST-80 as a guidescope but I didn't really rate it for photography. I have no experience of the ST-102.

1 minute ago, JamesAstro2002 said:

Cool. As @Stub Mandrel just said I probably will just have to buy a CC again, I've realised just how bad the coma is without one. Did you require any extra spacers to get the right backfocus? Would you mind sending a picture of it?

I guess you have a few options but the SW and Baader seem the most popular, I think the SW one is a focal reducer too ? I use EFW and OAG and it defo needs spacing, I think I used about 1.5mm of delrin spacers alongside one of the standard ZWO (big) spacers that came with the camera. I can DM you some better pics and measurements tomorrow if you still need info.

4 minutes ago, JamesAstro2002 said:

Awesome! Thanks for the reply. What Coma Corrector do you use out of question?

I use a Baader MPCC mkIII.

1 hour ago, JamesAstro2002 said:

Hi all,

I've been thinking about cracking my 130pds out again for imaging with my asi 1600mm. Any other users of the 1600mm and this scope?

 

I have just started using a ZWO ASI 1600 with the 130 PDS. It's my first ever mono astro camera so I have lots to learn. I had a few issues with weight/tilt to start with, but I've identified the problem and have ironed things out a bit. Attached are a couple of images that were just part on my testing things out (just a few subs).

Looking forward to getting some clear skies to use the ASI 1600 properly now !

+1 for 130 PDS, I've used mine with a 600d and the 650mm FL works just fine with the crop sensor for many targets.

1 minute ago, wimvb said:

When you are in the market for a new camera, use a fov calculator to compare sensors.

http://astronomy.tools/calculators/field_of_view/

Also, for deep sky work, always go for a cooled camera. Dark frames need to match light frames in temperature, which is much easier to do if you can set the temperature of the camera.

I've been using that already and looking for smaller FOVs, trouble is it isn't all about FOV is it, gets a bit more complicated than that. I would be looking for cooled for sure.

Thanks again👍

Yeah Juan did a good job on my 600D a couple of years ago. Very happy.

More recently I used Andy at Astronomiser to modify my 6D. I did this because he was the only person I could find in the UK that would touch a 6D. That turned out good too.

http://www.astronomiser.co.uk/

On 25/03/2020 at 19:28, wimvb said:

My ASI174MM has 5.86 um pixels, and at 1000 mm focal length, my images are still moderately oversampled most of the time. Detail in your images will depend more on sky conditions and tracking (guiding) accuracy, than on pixel size. With smaller pixels, the signal will be smeared out across more pixels. Each pixel collects light from a smaller section of the sky than if you have large pixels.

With 1000 mm fl, and even with 650 mm fl, a 3.8 um pixel camera has enough "resolution" for any practical purposes, even for galaxy hunting. As for sensor size, you can always crop empty sky from a galaxy image. Small sensors won't give you larger or higher resolution images than large sensors. But they will give you smaller files to work with.

The main reasons I bought an ASI174MM, was that it has large pixels with a high full well capacity, and good pixel scale (arcseconds of sky covered by each pixel) at the focal length I wanted (1200 - 1600 mm at that time). Price was also an important factor. The small sensor meant that files wouldn't be large, and stacking would be faster. 

Thanks all for your replies, I might look into a 2nd hand asi 174mm. My budget is £0 at the moment but I am just planning ahead for future savings !

I had to upgrade my bolts when I bought a 2nd hand HEQ5, the stock ones were bent and difficult to adjust (very stiff), I had quite a job getting one of them out. Maybe it is worth carefully removing the bolts to check they are definitely not bent ?

The bolt upgrade was a good move for me, it solved my stiff adjustment problems, but one of the stock bolts did look a bit like a banana when I got it out !

+1 for ball head, I got a cheap one for my SAM recently and it works great.

https://smile.amazon.co.uk/gp/product/B073CW2JMZ/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

I’m lucky to live on the edge of a fairly quiet village with no big towns nearby. I often leave my gear for an hour or two in our back garden. Having said that the garden is well fenced with a double locked gate and the shed where I run stuff from is locked and alarmed when I’m not in there, so I have thought about security. I feel quite secure in this location but why take any chances !

Thanks mate.

Yep small FOV and high resolution is what I was after I guess for galaxies with my 1000mm ? I wasn’t quite sure if the 178-cool would be suitable or not. Can’t honestly say I understand much about pixels and image scale etc !

Any other suggestions for suitable cameras to investigate ?

Hi All

I’ve been thinking about a cooled camera for imaging galaxies with my Skywatcher 200 PDS (and maybe the 130 PDS).

I thought that the ZWO ASI 178mm-cool might fit the bill, not sure if that would be a good choice but looks like they’re discontinued anyway. I was just wondering if there is a newer camera with similar or better specs now available ?    

Thanks

1 hour ago, Norfolk Noob said:

What is the advantage of bypassing the handset?

No rights or wrongs here and I don’t think it really matters tbh. Personally I just see it as one less link in the chain to go wrong, less equipment to rely on and also you get to keep your handset in good nick. I prefer just to have a single direct cable between PC and mount, less clutter !

I use cartes du ciel and eqmod to control my HEQ5, it works great and takes the handset out of the equation. For this approach you need an EQMOD cable that connects your PC directly to the mount.

https://www.firstlightoptics.com/blog/eqmod-controlling-the-heq5-neq6-and-other-mounts-directly-from-a-pc.html

When I first started I didn't understand any of it but I followed a few youtube tutorials to get me up and running. This one was the simplest and most helpful for me in the early days.

6 hours ago, cletrac1922 said:

First of all welcome from Land Down Under

I have been looking as well, and my local astronomy shop also advise to run with the ZWO ASIAir WiFi unit

John

Thanks. I hope to connect mine via a powered USB hub to my laptop. 👍

1 hour ago, tooth_dr said:

Hi Gary

I recently was setting up my SW autofocuser on my scope, and noticed that the motor was slipping on the spindle.  I went to investigate and noticed there was no way of actually tightening the motor coupling to the shaft, but that it appeared to rely on friction.  I drilled a hole in the coupling, and threaded it to allow me to directly tighten it up to the shaft.  It not longer slips.  And if it goes to the full travel of the focuser, then the spindle itself slips against the little teflon block, and prevents any damage.  Could you try that?  I'll try to post pics from my phone shortly.

If the spindle itself is spinning then this EAF isnt going to cure the problem you have.

Hi Adam

YES, this is exactly the problem and I had the same experience with diagnosing the problem. The motor slips on the spindle, the spindle doesn't slip. Frustratingly if I tension the actual focuser anything above lightly (to hold the weight of the camera/EFW etc) the motor then slips on the spindle and it becomes useless.

I've ordered the ZWO EAF so I hope this can be tightened directly to the shaft via a couple of grub screws and drive the now well tensioned focuser without slipping.

Thanks for the help with this, I've ordered one today. 👍

Thanks everyone, this is all good information for a mono newbie like me !

I saw that most folk use the same sub lengths for their RGB so I sort of assumed that was normal practice. I was trying to understand the processes involved and work out my own sweet spot for camera settings/exposure times, I felt I had to ask this question when I found differing ADU values (I was expecting them to be closer), I wasn’t sure how important the difference in values were.

Anyway, I’m just feeling my way around and trying to get my gear working. I am at the point now where things are not bad (after a headache with a wobbly focuser tube), I think I have some reasonable settings, I can start imaging.

I took my first ever RGB frames on Thursday night and I combined them today, this is the result. It was purely a test to see if I could learn the process, not really a target for me as such it was just available at the time.

This is 10 frames each of RGB with no calibration frames. OK, it’s not going to win any awards but I am just chuffed I’ve got a colour image out of a mono camera.      

Time to do some well planned imaging session now !

Thanks all for your help.

Thanks for the replies, this is helpful.

I use APT at the moment for focusing. Would you say the EAF steps are repeatable ? I mean can I store focus points in APT and return to them later on and fairly accurately ?

Thanks

Hi all

I’m trying to get to grips with my new ZWO ASI 1600 its very different from my previous DSLRs and I want to try and get things right if I can !

So….. here’s a newbie question. Do people take different length exposures for different RGB filters ? I’ve been looking at the median ADU values for my RGB filters tonight and they are all slightly different.

Red = 1216

Green = 1360

Blue = 1328

Is this important, do I need to adjust exposure times for each filter to try and get closer ADU values ?

Thanks

1 hour ago, blinky said:

Yep, I have one, really good, works well nothing negative to say about it really

1 hour ago, CaptainShiznit said:

I got one recently on my 130pds which holds a DSLR with coma corrector and LPS filter in the focuser. Had no issues at all hardware wise except needing to buy different screws as the supplied ones didn't fit my focuser. Software wise I use APT and the autofocus doesn't do a great job. Could be my fault, could be dim stars through either light pollution or the filter. I tend to just focus manually within APT. It's great to be able to see where the focus is represented by a number and to have such fine adjustment.

I would recommend it.

Thanks both for replying.

Would you say it is up to carrying a mono camera + EFW + OAG + MPCC on a well tensioned focuser ? Weighs just under 1.3 KG. 

Hi all

Just wondering if anyone has one of these and if so what you think of it ?

I need a better autofocuser because my Skywatcher autofocuser just slips on the spindle when the focuser is tensioned up sufficiently to carry heavy imaging gear.

The ZWO EAF seems like a neat package at a reasonable price (compared to competitors).

Thanks

Here's mine, prolly won't help you much, looks like you've already established that yours is too long.

They're a good upgrade tho, my original bolts were getting bent. Got mine off ebay 3-4 years ago, just had a look back but ebay only lets me go back to 2018, sorry.