Wit's end...

[pipnina]

When I first computerised my mount I expected this hobby to become a bit easier, and certainly for the level of automation to make me able to image more frequently and collect more & better data when I did. Sadly since I made the move to a cooled mono cam with this computerised setup my imaging life has been anything but stress-free.

Has the quality of my images gone up? Certainly. Has it introduced numerous independent problems that make me generally unsatisfied with my equipment, even though it has more than tripled in cost relative to last year? Unfortunately...

Whether it be poor flat frame calibration (neither 130-PDS nor TS-Photon 200/800 are free from this...) tracking/guiding woes, collimation challenges, suspicious levels of vignetting, filter reflections, computer errors, heavy mono cam & filters sagging the focuser or plain not sitting straight, the TS telescope not actually being compatible with their own coma corrector... It's all left me very sad and frustrated and with far less imaging time and lower-quality images than I expected if these problems did not exist.

When I finally got fed up with trying to tinker with my 130P-DS, and went for the only real option in my budget at the moment without sliding backwards in aprture and focal length (TS-Photon F4) I realised that while this scope solved one issue (PDS compression-fittingless focuser and barrel intrusion) it introduced several more such as the coma corrector pushing focus so far out, that the tube can't extend far enough and the corrector has to sit about 3-4cm pulled out, meaning from the stock of the focuser to the flange of my camera I now have a whopping 12cm gap, which is just ludicrous and creating a massive torque on the tube and focuser when my 1.5kg of camera, filters and CC are sitting in it parallel to the ground. This shows in my images as well as stars change shape throughout.

Then the filters, I adopted the "buy once cry once" approach and bought chroma 36mm, which are supposed to be an ideal fit for APS-C sized cameras. But while the LRGB filters seem to be working fine, the even more expensive narrowbands produce horrible reflections around bright stars, no matter the orientation:

As you can see the reflections are present in this 3nm Ha filter whether the coated side is facing the camera or the telescope (I flipped the filter wheel around). This is only a 60s exposure of arcturus. I guess my hopes of a good narrowband session near orion's belt are shattered now! This pattern doesn't show up in lum, so it's definitely something to do with the narrowband filters.

Then there's the suspicious vignetting (ADU in a flat or the background of a luminance frame) of about 50%! This scope advertises it's "90% illuminated zone" at being far larger than the diagonal of my camera... And I have already reduced the distance between my sensor and the filters as much as the 17.5mm backspacing built into my cam allows.

 

And perhaps most frustrating of all, my mount wants to just... turn itself off randomly as of late. Sometimes the INDI control panel says it's outside of its alt-az limits (even if I turn those limits off in EQmod, it still does it), sometimes it claims it wants a meridian flip, sometimes, just nothing at all. All I have to do is press the button in ekos to start tracking again but not having to babysit the scope was meant to be an advantage of computerising it! Plus the drift it causes means I have to re-create the framing all over again.

 

 

At this point I just don't know where to go with this hobby. It's so so good when things are running well, but oh so horrifying when getting death by a thousand cuts when so many thousands of pounds turns out to be not so well spent as expected... What do I do!? Where do I best direct my current astro-savings project money to?! So many problems and (after the computer and camera upgrades) not enough money to just splash out and hope high end gear will fix it.

 

If anyone has any ideas I'll gladly hear them, because this is getting ridiculous : (

[Rallemikken]

Many things here, I'll focus on the "Raspberry PI 4". I don't trust theese small gadgets to run a full KStars/Ekos/INDI session, if that's what you are doing. To many toss away KStars and Ekos because troubles like those you describe, common for them all is that they try to run their rig from a PI, either a homebrewed setup or commercial.

How many run their gear with a grown-up laptop or computer, with KStars/Ekos/INDI under it's native OS, Linux? Well, there must be more than just me....  How many of us bring all kinds of frustrations to this table, trying to sort out all kinds of weird behavior and bugs? None. as far as I know, but I'm kind of new on this forum.

I'm a newbie, I fired up my rig for the first time on the 14. sept. and closed the season on the 8. april. On 64 degrees, to light summer. My log for my first year has 39 entries, and my harddisk has 45 new datasets. Not a single crash or hangup, not a single instance of "weird" behavior. Once the initial settings was sorted out, things just worked. The only thing I will continue to tinker a bit with is the guiding, but that's a thing we never settle on...

My rig is run by a HP EliteDesk 800 with Linux Mint 20.3 _64-bits. If you can't take your computer out, or the evenings gets to cold, consider running a PI on your rig as a pure headless INDI-server, and connect it to your computer that runs Linux/KStars/Ekos/INDI with an ethernet cable. Takes some effort and skills, but it's the nest best. I set up a PI3 B+ as an exercise and did a test with my Canon 600D connected. It was impossible to get the PI to consume more  than 152 mb of the PI's 1 gb, and the CPU-usage never got over 7,5%.

Btw, don't put anything between a camera sensor and the secondary mirror in a reflector. Period.

[pipnina]

1 hour ago, Rallemikken said:

Many things here, I'll focus on the "Raspberry PI 4". I don't trust theese small gadgets to run a full KStars/Ekos/INDI session, if that's what you are doing. To many toss away KStars and Ekos because troubles like those you describe, common for them all is that they try to run their rig from a PI, either a homebrewed setup or commercial.

How many run their gear with a grown-up laptop or computer, with KStars/Ekos/INDI under it's native OS, Linux? Well, there must be more than just me....  How many of us bring all kinds of frustrations to this table, trying to sort out all kinds of weird behavior and bugs? None. as far as I know, but I'm kind of new on this forum.

I'm a newbie, I fired up my rig for the first time on the 14. sept. and closed the season on the 8. april. On 64 degrees, to light summer. My log for my first year has 39 entries, and my harddisk has 45 new datasets. Not a single crash or hangup, not a single instance of "weird" behavior. Once the initial settings was sorted out, things just worked. The only thing I will continue to tinker a bit with is the guiding, but that's a thing we never settle on...

My rig is run by a HP EliteDesk 800 with Linux Mint 20.3 _64-bits. If you can't take your computer out, or the evenings gets to cold, consider running a PI on your rig as a pure headless INDI-server, and connect it to your computer that runs Linux/KStars/Ekos/INDI with an ethernet cable. Takes some effort and skills, but it's the nest best. I set up a PI3 B+ as an exercise and did a test with my Canon 600D connected. It was impossible to get the PI to consume more  than 152 mb of the PI's 1 gb, and the CPU-usage never got over 7,5%.

Btw, don't put anything between a camera sensor and the secondary mirror in a reflector. Period.

I can try running it using my laptop tonight, so try and eliminate the RPI as the issue.

My laptop and desktop are on Linux (laptop is on Ubuntu 20.04 Gnome, PC on Manjaro KDE), but my laptop has had its own quirks with Kstars/Ekos, namely it crashed when trying to platesolve, and wasn't able to use the polar alignment feature either.

Not sure why you think nothing can go between the secondary and the sensor when a key part of all reflector imaging trains (unless planetary imaging, but then barlows are common) is a coma corrector or field flattener etc. Plus many professional observatories have very complex optical systems with numerous mirrors, filters etc. Maybe the stuff I have between my secondary and sensor aren't right for my scope, but I don't see what's wrong with the concept.

[ollypenrice]

I feel for you. That's why, to the amusement of many, I do nothing via PC which I can do by hand. Doing things via PC automation and control gives endless advantages till it stops working. How often does it stop working? Pretty often, say I, as the host of six remote imaging rigs. Computers promise the Earth and deliver... earthquakes.

If you don't want to faff about with the optics, buy a refractor of proven performance. Don't read glass specs (FPL  52/53, yappety-yap, doublet-triplet-quadruplet-sextuplet-octuplet.)  Just look at the images they produce. Your budget will only allow something with a bit of blue bloat? Fix it in post-processing.

Olly

[Rallemikken]

10 minutes ago, pipnina said:

Maybe the stuff I have between my secondary and sensor aren't right for my scope, but I don't see what's wrong with the concept.

Call it superstition. The beaty of the reflectors is the fact that the photons travels freely, all the way from far-away to your camera sensor. Every artefact or fault on your subs can be traced to the telescope itself, which often can be enhanched and modded. Being a little more serious, I've heard it more often causes troubles on reflectors than refractors. That being said, it might be that the refractor guys are more capable of handling such things, as they rely on lenses for everything. Anyway, I've learned to deal with the slightly oblong stars at the fringes. And I'm lucky to be living under dark skies.

[Ratlet]

I've never been more annoyed with my own ignorance than I am right now.  I feel for you buddy and I really hope that someone will be able to help.

Do the reflections persist even with no filter in the train?  I'm just thinking the issue might be internal reflections in the tube rather than the filter themselves.  Perhaps the lrgb have lower enough transmission to prevent the reflection being visible whilst your higher spec chromas are allowing the reflection through.  If they persist without the filters then you know it's not the filter.

If it's the tube then flocking might be a solution.

 

[pipnina]

arcturus ha test - filter facing scope.fitsarcturus ha test 2 - filter facing scope.fitsarcturus lum test.fits

27 minutes ago, Ratlet said:

I've never been more annoyed with my own ignorance than I am right now.  I feel for you buddy and I really hope that someone will be able to help.

Do the reflections persist even with no filter in the train?  I'm just thinking the issue might be internal reflections in the tube rather than the filter themselves.  Perhaps the lrgb have lower enough transmission to prevent the reflection being visible whilst your higher spec chromas are allowing the reflection through.  If they persist without the filters then you know it's not the filter.

If it's the tube then flocking might be a solution.

 

Luminance filter seems clear of it (I forgot to turn my light panel off so it has a gradient however. These three show luminance filter, and hydrogen alpha with the coated side facing the camera, then facing the telescope.

EDIT: This person has a similar issue, but I don't see if they have chromas too or another brand, but they do have another reflecting scope: https://www.cloudynights.com/topic/731527-first-light-zwo-asi294mm-pro-mono-edgehd-11/

Edited May 28, 2022 by pipnina

[pete_l]

All I can offer is non-specific advice that applies to many areas. Whether computers or not.

The first step is to strip everything down to basics. Make sure your mount has no rattles, sticky spots or loose connections. Give them a good shake. Nothing should move or disconnect.

Then connect your computer. Do the same. Wave it in the air. Turn it upside down. It has to work unconditionally. Cable-up the mount and make sure it talks to the computer 100% of the time. Wiggle the cables, check for drop-outs. Run the CPU up to 100% and convince yourself that everything is solid and continues to work.

Be aware that none of the connectors used in most budget equipment are designed for outdoor use. Nor do they stand up to unplugging frequently. They are generally cheap garbage. As are the cables!

Do slews. Do flips. Add weights and repeat. Make sure that no cables snag at any point. Add your OTA. Do all the same again. Ensure everything is tight - no slack, no play. 

Continue the same with your camera. Use the simplest possible optical path. No adapters. No filters or correctors. Satisfy yourself that the images are exactly what you expect.

Add guiding. Recheck everything and continue adding one item at a time and retesting. Then, when everything is satisfactory MAKE ABSOLUTELY NO CHANGES EVER AGAIN. 😆

[david_taurus83]

I suspect those reflections are to do with the coma corrector. Which one is it? The Baader one is known for this, or an earlier version or something. That's an easy check though, remove it and try with no corrector. If the reflections go away then your expensive filters are OK. 

Regarding the PI. I use a Stellarmate for my mini portable setup. It has its quirks but it runs off a powerbank and if you know your way around Ekos then it's not hard to get going. Would I use it for my permanent pier setup? Not a chance. I bought a cheap mini PC off Amazon a few years ago with Win 10 Pro and it hasn't let me down once. Never crashed, switched off, failed to connect a device. Just works and its left on 24/7 in the shed and I control everything over VNC.

 

[discardedastro]

I totally feel the frustration. I will say that the Pi 4 can absolutely reliably run Ekos/KStars/INDI, and a desktop session for it all, though - I would focus on configuration quirks.

I've had the tracking stop because the mount exceeded limits according to KStars - I found that going in and enabling and then disabling all of the limits at the start of a night resolved this. Odd meridian flip behaviour is definitely a KStars/Ekos issue - my only advice on that front is to update fully because there have been improvements in that logic of late.

I'd also get super methodical with what you do. Write a checklist for session startup and shutdown. If you can, use the Ekos scheduler - this way, if stuff fails then Ekos will at least retry things for you, and you can use it to plan your imaging for the night ahead.

Totally agree re making sure power and mechanics are all good and working properly. Make sure you can slew without seeing significant voltage drops on your power supply, for instance.

In terms of the reflections and optical issues - I would again just get very methodical. Start with a bare OTA and a flat field, and gradually build out your optical train (for components with glass), using spacers to replace parts as needed. This you can do on a kitchen table with a flat panel. If that doesn't show up an immediate culprit, repeat the same with a star test.

I'd also consider light leakage on the reflector, in addition to +1ing the coma corrector comment above. Flocking the tube and blocking up any ports/potential light leaks is cheap and easy to do, and will do no harm.

Mechanically, making sure your focuser is properly adjusted may help with any bending due to long optical train lever arms, especially tension and clamping onto the tube at the base. But I would say the biggest upgrade by far I did for my OTA and imaging stability/happiness was a focuser upgrade, and it's one of the cheaper things to do in any case (and portable, if you ever decide to upgrade your OTA!).

[ollypenrice]

1 hour ago, Rallemikken said:

Call it superstition. The beaty of the reflectors is the fact that the photons travels freely, all the way from far-away to your camera sensor. 

But they don't. An incident photon is absorbed within the surface of the mirror and a different one is released - etc etc!

Olly

[Rallemikken]

4 minutes ago, ollypenrice said:

But they don't. An incident photon is absorbed within the surface of the mirror and a different one is released - etc etc!

Naahhh...  Arn't you confusing photons with electrons? Photons are massless waveparticles? They kick loose an electron when they hit your sensor, but I doubt that they can dwell on the surface of my mirror for any lenght of time??

[ollypenrice]

10 hours ago, Rallemikken said:

Naahhh...  Arn't you confusing photons with electrons? Photons are massless waveparticles? They kick loose an electron when they hit your sensor, but I doubt that they can dwell on the surface of my mirror for any lenght of time??

In my (amateur) understanding the incident photons energize the atoms they strike and these atoms then emit a photon of equivalent energy. Is it accurate to consider this 'the same photon,' whatever that might mean...?  Weird stuff. 😁

Olly

[Clarkey]

13 hours ago, ollypenrice said:

In my (amateur) understanding the incident photons energize the atoms they strike and these atoms then emit a photon of equivalent energy. Is it accurate to consider this 'the same photon,' whatever that might mean...?  Weird stuff. 😁

Olly

From my rather rusty quantum theory, it must be the same photon for two reasons:

Firstly got the atom to emit energy it needs electrons to move from one specific energy state to another and will only emit certain wavelengths. Given this is not the case, it cannot be happening. (Hence the ability to look at emission spectra).

Secondly, if the photon was to be absorbed and re-emitted it would be in a random direction.

As for the reflection mechanism itself...🤔

Going back to the OP, I only have experience of the F4 TS scopes. In the case of my 6" version I had to replace the focuser, flock the tube and buy a new CC to get reasonable results. Also, I had horrendous reflections that were impossible to filter out. I  going to try it with a OSC camera later to see if this helps.

Unfortunately AP is a frustrating hobby with all its quirks. I have missed countless imaging sessions due to something not working. As stated above, gradually get rid of the problem kit and work methodically. When you get that one excellent result the pain goes away. (Well, mostly). I wish you luck.

 

[pipnina]

25 minutes ago, Clarkey said:

From my rather rusty quantum theory, it must be the same photon for two reasons:

Firstly got the atom to emit energy it needs electrons to move from one specific energy state to another and will only emit certain wavelengths. Given this is not the case, it cannot be happening. (Hence the ability to look at emission spectra).

Secondly, if the photon was to be absorbed and re-emitted it would be in a random direction.

As for the reflection mechanism itself...🤔

Going back to the OP, I only have experience of the F4 TS scopes. In the case of my 6" version I had to replace the focuser, flock the tube and buy a new CC to get reasonable results. Also, I had horrendous reflections that were impossible to filter out. I  going to try it with a OSC camera later to see if this helps.

Unfortunately AP is a frustrating hobby with all its quirks. I have missed countless imaging sessions due to something not working. As stated above, gradually get rid of the problem kit and work methodically. When you get that one excellent result the pain goes away. (Well, mostly). I wish you luck.

 

Which CC worked for you in the end, and what focuser did you use to replace the default one?

 

Also yes, when things are working it does make it all feel worth it again.

I got this as a little test when I got stuff working reliably on the computer side, and just about got the telescope OTA to look collimated and mostly untilted. Quick 10-min sub in Ha on the elephant's trunk. I'm honestly surprised that I got so much in so little time.

Edited May 29, 2022 by pipnina

[Clarkey]

3 minutes ago, pipnina said:

Which CC worked for you in the end, and what focuser did you use to replace the default one?

I ended up using the SW Aplanatic but it does stick out. I used a parfocal ring to hold it in the right place. With the Baader ST focuser it did not give any tilt issues. However, putting the ST on a 6" scope was a bit of a challenge.

[pipnina]

11 minutes ago, Clarkey said:

I ended up using the SW Aplanatic but it does stick out. I used a parfocal ring to hold it in the right place. With the Baader ST focuser it did not give any tilt issues. However, putting the ST on a 6" scope was a bit of a challenge.

Hmm, in theory the SW Aplanatic is the same as the one I am using (TS-GPU), just rebranded GSO stuff.

What kind of parfocal ring were you using?

 

Also: I think with our focal point so far out on these scopes, we might be inherently vignetted by the focuser. I put the properties of the 8 inch photon into this site and it shows a pretty grim story:

https://stellafane.org/tm/newt-web/newt-web.html

[alacant]

Hi

Can you simplify this? Hanging a heavy monochrome setup on unmodified low-end-of-the-market telescopes and focusers is, well...

Borrow a DSLR or osc and bring the rest of the hardware up to standard first perhaps?

A few bits to try with what you have ATM could include:

-Give yourself a chance: go with a powerful Ubuntu LTS gaming box.

-Get a proper GPU cc. These leave the focus position unaltered and come with a graph and chart giving the correct spacing wrt focal length.

-Get the latest indi/ekos/kstars from the repositories. We'd also recommend building the latest versions from git. Try that too.

Cheers 

Edited May 30, 2022 by alacant

[Elp]

I empathise with you.

Anything astro related isn't easy at the best of times, trying to image multiplies the number of things that can go wrong.

Summary of issues I've had last year from summer until around winter: polar alignment routine not working (ie showing I was way out of alignment when I was clearly not), tracking not calibrating, tracking not working, runaway guiding, goto not working, mount performing strangely due to how it was powered, camera disconnecting due to power draw thus pausing on ongoing shooting plan so I couldn't leave it running unattended, can't get focus on solar, camera freezing with raspberry pi... Probably a few more.

I tend to keep a list of issues and then try to address each one separately sometimes days/weeks apart, if they can be done during the day this helps a lot but most you have to wait until a clear night. With perseverance and a little help (and usually a lot of self research) you will find solutions and overcome each issue.

One thing I note with your original post, you state your image train is parallel to the ground? Due to the weight most people using reflectors have their image train hanging (precariously) perpendicular to and pointing toward the ground for this very reason as it also helps with telescope balance.

Can't comment about your filter reflection as your state the lum one is fine and from my experience narrowband filters should likely do the opposite as they reject so much light in the first place, I've only had odd issues when I place a filter on the front of a DSLR lens, due to being exposed and catching stray light at angles they cause all sorts of weird patterns, the Optolong OSCs in particular.

It's an added expense but something for you to consider: Once I added an Asiair into my system, this alleviated a lot of frustration I was having with the astroberry/ekos/indi controlled raspberry pi. It's so simple and is quite literally plug and play. It has transformed my sessions considerably, also no pc needed (still need a pc to process the images though after). I still have the raspberry pi mainly for solar and planetary work, if I had more clear nights at hand I'd probably eventually get it working right for nights but being limited with time you want it working asap with minimal fuss and the rpi didn't offer it, plus the simple asiair interface works better on a mobile device which is a major plus.

[pipnina]

58 minutes ago, alacant said:

Hi

Can you simplify this? Fighting a monochrome setup is, well...

Borrow a DSLR or osc and get the rest of the hardware working first perhaps?

A few bits to try.

-To begin with, give yourself a chance: go with a powerful Ubuntu LTS gaming box.

-Get a proper GPU cc. These leave the focus position unaltered and come with a graph and chart giving the correct spacing wrt focal length.

-Get the latest indi/ekos/kstars from the repositories. We'd also recommend building the latest versions from git. Try that too.

Cheers 

The only cc I can find is the TS GPU, which is the one I am using at the moment, but claims to push focus out by 20mm https://www.teleskop-express.de/shop/product_info.php/language/en/info/p6706_TS-Optics-NEWTON-Coma-Corrector-1-0x-GPU-Superflat---4-element---2--connection.html

After making this thread I decided to do as you say: I used my laptop (Ubuntu 20.04, i7-6700HQ / 16GB ram, high enough end to have a USB C port back in 2016 when I bought it) in place of the raspberry pi, and had it only hosting the indi server and running PHD, while my desktop used Kstars to remote control the PHD2 app and indi drivers. That much seemed to solve the computer issues, though I think I will have to get a mini PC of some sort as, despite leaving so many thousands of £ out overnight already, that laptop is quite expensive and also needs to be used for work quite often.

I avoided using it in favour of the raspberry pi originally as the RPI was cheap and many had claimed it to be effective for the purpose, and my laptop had some issues with kstars which have been resolved with recent updates (such as crashing on platesolve and failing to move the mount during the polar align routine).

[alacant]

21 hours ago, pipnina said:

a mini PC of some sort

I'm glad you've sorted out the hardware. You really do need to be able to take the server-side for granted. We host using refurbished stuff such as this. 

Go back to the rpi when you're familiar with the workings. Try different clients, although the EKOS scheduler is hard to beat these days.

The client end doesn't need to be anything special. Run kstars/EKOS on the server and connect over vnc. Your 'phone would be fine. Just remember though that if you're out and about, always connect over Internet through ssh.

21 hours ago, pipnina said:

The only cc I can find is the TS GPU

Proper GPUs can be had on AliExpress and various other outlets, including a few of the original sw aplanatic.  The type you need is like this.

Good luck and HTH.

EDIT: Both your telescopes will need modifying to bring them to imaging standard.

This includes but is not limited to: 6 strong primary mirror springs (3 active and 3 passive over the locking screws, leaving the latter loose), primary mirror floating on neutral silicone sealant, tube rings spread further on a Losmandy dovetail plate and tied along the top with a rigid aluminium box section, lightweight secondary support -for the gso- are the minimum we've found that will retain collimation at all angles.

 

Edited May 30, 2022 by alacant

[iantaylor2uk]

On 28/05/2022 at 20:52, ollypenrice said:

But they don't. An incident photon is absorbed within the surface of the mirror and a different one is released - etc etc!

Olly

There are various ways in which photons can interact with the mirror that results in a reflection. However it is meaningless to say whether the reflected photon is the same as the incoming photo since photons are indistinguishable from each other.

[wimvb]

I subscribe to the undulatory theory for light propagation, and leave the corpuscular theory for emission and absorption. Huygens over Newton.

As for the RPi, it is quite adaquate for astrophotography automation. In fact, the youngest generation of sbc’s are quad core or hexa core; far more powerful than many a laptop used in the field.

I have Ekos/Kstars on a RPi4 which controls mount, focuser, cameras and filterwheel. It guides, focuses, flips, and plate solves without any hickup, while I sit comfortably indoors.

[alacant]

5 hours ago, wimvb said:

guides, focuses, flips, and plate solves without any hickup

So do ours. The OP's however, doesn't. We'd really like to get to the bottom of why they sometimes work, sometimes not.

Having said that and although I'm sure that the OP doesn't fall into this category, we always start INDI beginners on either a laptop, or a mini with a screen and keyboard attached. Very few grasp the idea of client-server, especially experts more familiar with other popular platforms. The migration to headless seems far less traumatic that way around;)

Cheers

Edited May 30, 2022 by alacant

[wimvb]

2 hours ago, alacant said:

So do ours. The OP's however, doesn't. We'd really like to get to the bottom of why they sometimes work, sometimes not.

This was partly a reaction to a reply to the original post. The weak point with RPi in my experience is either the power supply not being up to the job or problems with usb cables. A few years ago, drivers were a possible cause. But these have become a lot better. For me, my eq mount and Pegasus focus cube sometimes interfere with each other. Both have similar ttl-serial chips that seem to confuse the RPi usb ports handler.