Pitch Black Skies

You're welcome. To go a step further than levelling the focuser, align it so that it is perpendicular to the opposite side of the tube. In fact this should be done before ever collimating the telescope IMO. This gent does a great job at explaining it. It starts at 27:15.

Have you verified that the doughnut is centred while you had the primary out? It isn't really connected to the problem you're having with the off center laser dot, but it's good to know for that extra level of accuracy. I've had to recenter the primary spot on every new telescope I've bought so far.

The template included with the Cats Eye by Jim Fly is a useful tool for this.

BTW if the spider vanes are over tightened they can pull the OTA into an oval shape. Not a deal breaker, as long as the focuser is aligned and the secondary is concentric to it.

Keep at it, you will figure it out.

5 hours ago, Stardaze said:

Is it simply that the slight tilt on the primary when aligned with the secondary (collimated well) does throw it off centre?

No. Tilting the primary doesn't move the dot out of the doughnut at all. The dot location on the primary is determined by how the secondary is reflecting the laser beam.

To get accurate collimation one must always ensure the dot is in the centre of the primary prior to using the Barlowed laser technique for the primary alignment.

Having said that, sometimes a laser can have one believe the secondary is collimated by showing the dot in the centre of the primary. Under closer inspection one might find that the secondary is slightly rotated and tilted more on one side to account for it.

I was a big fan of using a laser for collimation too but after more experience I am now wary of them for the reasons listed above.

IMO a very accurate way to collimate is by using a Cheshire sightube for the secondary alignment, then ensure it is rotated properly and that the three primary clips are even in the secondary. Then simply use a collimation cap to ensure the primary is collimated. As you peer through the collimation cap everything should look completely concentric.

When you know everything is completely concentric, then pop your laser in to see if it agrees. If it does, there might have been a slight tilt in your secondary. If it doesn't, the problem is with the laser, and from experience it is possibly with how it is seated in the holder.

Despite starting with a 6" dob myself, and progressing to an 8", and then finally to a 12". I think if like you mentioned your main interest is the moon, Saturn and Jupiter. A better choice for these targets would be a mak.

I would still echo what the others have said though, dobs are a great beginner scope. They are good at a lot of things and give plenty of bang for the buck.

Either way, I hope you have fun with the hobby, and welcome to the best forum on the internet! 🤝

9 hours ago, raadoo said:

I'll try and do a quick write-up of what I did, but keep in mind, this was all done on a non-linear, compressed JPG, so doing the below on the original data should yield much better results, both in terms of noise and star reduction, and detail enhancement. I've also attached a screenshot of the layers panel in Photoshop, so hopefully it's not completely dry reading 😀

• saved the JPG as a 16bit TIF (this was necessary for the next step and further edits being as non-destructive as they can be)
• used Starnet++ to separate the stars from the nebulosity
• opened both starless and original in Photoshop (from here on out, it's just Photoshop, by the way) and did the classic Difference blending of the two to create a Nebulosity layer and Stars layer
• Nebulosity:
  • applied frequency separation so I can work on the detail enhancement without affecting colour
  • colour layer was left mostly untouched until later steps (though I did do some White Balance and slight saturation adjustments in Camera Raw)
  • for the detail layer I mostly used High Pass and Camera Raw to sharpen and enhance texture and detail, while also throwing in the odd Noise Reduction along the way
  • in the detail layer (which is mostly 50% grey by this time, bar the actual detail in the galaxy), I also took a grey brush to the core of the galaxy, to remove the banding that was happening in the original
  • merged the frequency separated layers and did more cosmetic / colour work using Camera Raw together with some blended LUTs
• Stars:
  • slightly increased the saturation as the whole Starnet++ process usually leads to undersaturated stars
  • created a Highlights mask which was then used to reduce most of the stars' bloat
  • a few of the stars have diffraction spikes that the mask messed up, so I manually went in and brought back the original spikes for those
• merged the whole thing and uploaded it

My experience with StarTools has been very limited, but from what I can tell you could probably replicate the steps above without much hassle and with likely better results; especially as there seems to be a way to use Starnet++ in linear mode!

To be honest a lot of that has gone completely over my head but I will revisit in the future and can hopefully make some sense of it when I have accumulated more knowledge and experience.

For my image I just copied this gentleman's tutorial on YouTube. That is all I am really capable of at the moment.

"ASIAIR PRO is a smart WiFi device that allows you to control all ASI USB 3.0 cameras, ASI Mini series cameras, and Mainstream DSLR cameras. (It can not support ASI120MM/MC camera)"

Does that mean the ASI120mm Mono guidecam is not supported?

1 hour ago, adyj1 said:

I think when recommending the asiair to beginners we should really point out early in the conversation that it only supports ZWO cameras if you switch to a dedicated astro camera (for dslrs it is fine). I have a ZWO camera myself so don't think this is the worst limitation in the world, but it is quite a unique 'feature' compared to the alternatives that needs to be highlighted. 

(only posting this as there's been two different recommendations without this rider) 

I don't know enough about it but it seems like a great piece of equipment. Maybe it is something I will progress to.

1 hour ago, StevieDvd said:

Good starting point. With an eqmod cable (or Synscan wifi) you can connect to a computer and have a choice of PA software.  The same cable would be used by a PC or one of the Linux solutions so money well spent. As mentioned above by others you will also need to connect the camera, via a USB lead, to the same computer to see the PA images used in the process.

 

 

I would opt for the WiFi adapter over the cable for the luxury of controlling the mount from indoors, however I am restricted by 1m camera usb cable.

My camera has Bluetooth and WiFi capability but I can't seem to get NINA to detect it other than connecting via the USB cable.

11 hours ago, raadoo said:

I had a stab at processing it (hope you don't mind) and I noticed a couple of things:

• there seems to be some backfocus issue with the sensor being to far back (stars in the corners take are circularly distorted around the center of the image)
• 120s @ ISO 25,600 is far too much exposure for Andromeda's core which, subsequently, got blown out. Now, there's not much you can do about blown highlights, so, when that happens to me, I just lean into it rather than try and fix it by going ham on the Highlights adjustment, as this leads to grey light instead of white and, to me, looks off.
• interestingly, even if the stars are not fully in focus, the arms have a ton of detail in them, which is a very cool surprise

My first attempt at M31 didn't even include a tracker of any kind, just a 300mm f/5.6 lens, a DSLR, and me manually cranking out 5s exposure like an absolute madman and the result is more akin to how you'd see Andromeda through a pair of binoculars. All that to say, really good job! 👏

Wow, thanks so much! That is absolutely amazing.

I had a suspicion that my coma corrector might need to move a mm or 2 closer to the sensor. I think I had the focuser thumbscrew lock too tight which was tilting the focuser tube ever so slightly. I'm waiting for a clear night to do some more experimenting.

How did you get so much detail? Could I do this myself in Startools?

(Cranking out 5sec exposures like an absolute madman 😂 that got me).

7 hours ago, Richard_ said:

I echo Sunshine, a really good first! You've captured some nice detail in the lanes around the core. What software did you use to stack your subs and edit your final image?

The easiest improvement I'd recommend is to crop out the black bars at the top and bottom of your image as it's a landscape orientation posted in portrait orientation. 

Thanks Richard 🙂

I used DSS and then Startools.

I'm not sure what happened, I think I screenshot it.

9 hours ago, StevieDvd said:

It would help to advise if we knew what software you are currently using (if any) and if you intend to image away from home location. You may start imaging standing next to your scope but want to move on to leaving it to run - whilst you monitor control from indoors in the warm.

Your options range from using the PA alignment in the Synscan handset, no camera needed, to the purchase of a PA tool such as Polemaster.

Since Polemaster came out there has been a heap of software to make PA easier. Depending on what computer type you use (Windows, Mac, Linux) and how comfortable you are with using them, makes your choice a defining factor.

For example if you like Linux you can configure a system fairly cheaply to use at home or on location. A Raspberry Pi system running Astroberry, Stellarmate ir Asiair in order of cost (all have a PA utility).

Windows, it seems NINA is catching up with user friendly PA plugins too, and again free. Some capture software have their own PA as well.  For example, Sharpcap needs a cheap license to use the PA and works well if you can see the North/South poles (it can use a DSLR via a tweak in the process).  This is a bonus if you use Sharpcap for your image capture.

HTH

Steve

 

 

Hi, as mentioned I'm just using the polar scope on the mount.

I'm not familiar with any astrophotography software, it is all new to me.

I don't intend to image away from my home location.

At the moment I'm just setting a series of exposures on an intervalometer. I go back inside and when it's complete I return to bring everything back inside.

It appears the most logical move for me would be to learn how to polar align through NINA as the only thing I require for that is an EQMOD cable.

3 hours ago, adyj1 said:

... but you wouldn't be using the guidecam for your polar alignment in NINA - it uses your primary camera.

By all means get the guiding setup, as you'll progress to that quickly, but you already have just about all you need for PA using NINA (apart from possibly the EQMOD cable which should *definitely* be your next purchase if you haven't got one).

For the guidescope I have both the astro essentials and ZWO 32mm guidescopes, and they are fine. I prefer the AE one for usability and accessories. 

I'll let someone else comment on which of the colour or mono is the best choice - I have mono because all I want to use it for is to guide (and that was the first one to come up on the for sale forum 😉). Both will work. 

Ah I see, and the EQMOD cable basically just connects my mount to my laptop correct? I've heard something about a WiFi adapter too, would that do the same thing?

8 hours ago, ONIKKINEN said:

Dont have an opinion on the polemaster, except that i find it hard to think where i would put it in mine or even need it. Polar alignment options with platesolving are great and since platesolving is fantastic anyway, might aswell polar align using the same methods. ASI 120 and any decent 50mm guidescope will satisfy the needs for Sharpcap pro polar alignment and cost about the same as the polemaster. And you get a guiding setup as a bonus. To be honest i have not even considered methods other than sharpcap pro polar alignment since i tried it the first time. It is impossible to do wrong and never takes more than a few minutes. If there is a budget for the polemaster, then the guider route would also fit the budget, and be usable for more than one thing.

Platesolving in NINA happens through the imaging scope and camera. As long as your camera model is supported you will be able to platesolve and polar align (uses platesolving).

And by the way, if you have the newer synscan V5 model of EQ-5 you can just use a printer style USB cable to connect to the mount. This way you can actually use the handset and PC controls with your mount at the same time and you don't have to get a separate EQMOD cable. If you have the USB port in the bottom of your handset, you have the new model.

I don't have the USB port. My camera is a Canon 800D.

Sharp cap sounds great, but I was wondering if that would even be necessary as alignment can be achieved through NINA.

Would I be getting the ASI 120 colour or mono, or does that even matter?

What 50mm guidescope could you recommend? I think SVBONY do one that's quite cheap. Is the ZWO mini 30mm too small? I'm currently eyeballing the Astro Essentials 50mm or 32mm guidescope.

8 hours ago, adyj1 said:

You do realise that a polemaster likely costs MORE than a guide scope and guide camera? 

... and to get guiding working you're going to be pretty far down the road of connecting camera to laptop to mount and running NINA. 

I reckon you could get NINA working *just* to use the three-point polar alignment fairly easily - at least as easily as getting APT up and running, IMO - and then when you're ready it will be a small step to full-blown automated image acquisition ☺ . 

Just my 2p worth

Exactly what I was thinking. If I was planning to progress to guiding in the next couple of months, that would make Polemaster redundant as I could achieve perfect polar alignment through the guidescope and guidecam through NINA.

Do you guys have any experience with Polemaster?

Would it be a waste to buy if I was planning to upgrade to a guidescope and guidecam anyway in the future?

I believe I can platesolve with a guidescope and guidecam.

1 hour ago, ONIKKINEN said:

I was going to say sharpcap pro as its excellent, but im pretty sure sharpcap doesn't work with DSLRs. Still there are options left.

Have a look at this video from Cuiv of using the NINA polar alignment plugin: https://www.youtube.com/watch?v=JI1tzoBhkH8

NINA works with at least Canon and Nikon DSLRs and i don't see how the polar alignment plugin would be any different. I was platesolving with a 550D just fine for a while using NINA and Astap. Actually if you go through the (not that much) trouble to setup NINA and platesolving i think you'll find that NINA is great to use for other reasons too. Platesolving + sequencing + the framing tool + target list etc, great software and costs nothing at all.

There is also the D.A.R.V slew method: https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760 Sounds a bit time consuming but would work better than a polarscope alignment with some practice.

 

Excellent! Thank you

56 minutes ago, adyj1 said:

APT is probably easier to get your head around as a beginner (I used it for 3+ years) and but it doesn't have a PA routine, unfortunately. 

Watch this and tell me you don't want it 😉 

Ady

 

Looks great.

So there is a way I can do this through my DSLR and OTA?

4 minutes ago, Sunshine said:

I'd be over the moon if it were mine, its great!

Thank you so much 🙂

11 minutes ago, adyj1 said:

There is, but it's a slightly steep but worthwhile learning curve; control your mount with the laptop, and use astro capture software that supports semi-auto PA.

For windows, an EQMOD cable attached to your mount, ascom, eqascom and nina software (nina 1.11 nightly build) and the 'three point polar alignment' plugin. 

(I'm assuming you don't use Linux or you'd have mentioned it.Probably a couple of times 😂 ) 

Ady

Haha, thanks Ady, I have Windows 11. Does APT do the same as NINA, but maybe a little easier to use?

I made the schoolboy error of not adjusting the ISO back down after finding my target.

It's 52 x 120s, and my first ever 20 flats included with 20 bias, no darks.

ISO 25, 600

What are my options for a more accurate polar alignment? I'm just using the polar scope on my EQ5 pro. Attached to the mount is a 5" reflector and a DSLR attached to that.

Please note, I don't have a guidescope and guidecam.

Is there a way to polar align through my OTA and DSLR using a laptop and a software program?

15 hours ago, Bibabutzemann said:

If you made sure that the focusing is perfect, i would definitely recheck collimation. I dont know if its due to overexposure, but it doesnt look sharp.

Spacing could also be an issue ofc. What CC and spacing did you use here?

Do you have short exposures for comparison?

Hi there,

It seems to have sorted itself out after I relieved some pressure on the focus position lock thumbscrew.

The sharpness is likely down to the ISO 25600 and my post processing skills and software. It's one of my first astrophotography images.

6 hours ago, barbulo said:

If the coma effect is not even, I would say is the latter. Try the third thumbscrew solution (drilling the ring) or the compression ring/ClickLock one. That should get rid of the tilt (gravity is a tough adversary ⬇️ too).

I'm using it. I think I'm suffering from both. I'll try again tonight and won't go as heavy with the focuser lock this time.

First light on M31 with my 130P-DS!

It took about 2 hours to get polar aligned, star alignment, etc. Nothing was going right for me. Fumbling in the dark makes it all the more difficult.

Finally, I managed to get it going. I set it to take 2 hours worth of 120s exposures and then scurried for a warm cup of tea for my numb hands.

I later returned only to find I had left the ISO setting on 25, 600! I carried out an ISO experiment earlier in the evening and completely forgotten to change it back.. 🤷🏻‍♂️

Anyway, I managed to get this after a bit of editing ⬇️

In the corners it looks like a bit of radial distortion in the stars, more noticeably in the top left. After reading an article I think it might be because my coma corrector is positioned too far from the camera sensor or maybe the focuser thumbscrew lock is tilting the focuser tube?

Thanks!

The little mod really helps to keep everything centered.

If it's something you might consider doing you will just need a 3.3mm drill bit and an M4 tap.

If it's something you're not comfortable doing yourself I would be glad to help if you post it to me 👍

I use that exact 2" compression ring to hold a coma corrector and it is super secure and plumb.

However, I have modified it with the addition of a 3rd thumbscrew for equal pressure. 10 minute job if you have the tools and makes the world of difference.

HTH