wimvb

What you see around the single star is the diffraction caused by the mirror clips. To get rid of this, you'll need a mirror mask, a ring which you attach on top of the clips, and which covers them. This will decrease the effective aperture by about a cm, but that isn't necessarily a bad thing. You can 3D print your own mask, or buy one.

https://www.firstlightoptics.com/misc/backyard-universe-primary-mirror-mask-for-sky-watcher-250mm-newtonian-telescopes.html

Regarding the need to collimate, the Quattro is a fast newtonian where the secondary mirror is offset. This may mean that the secondary mirror holder is offset. If so, the out of focus doughnut will not be symmetrical. Another Quattro owner should be able to clarify this. (The alternative is that the holder is mounted symmetrically, but the mirror is offset on its holder.)

A small section of the Coma Cluster of galaxies.

This is 5 hours of RGB data on this galaxy-rich part of the night sky, captured with my MN190 and ASI294MM camera, and processed in Pixinsight. Captured during two clear nights April 11 and April 12.

For the annotated version I used the ngc/ic (pink), LEDA (blue), and GMP (yellow) catalogues. GMP is a compilation of 6724 galaxies in the Coma cluster, published by Godwin, Metcalfe and Peach in 1983. Apparently, this catalogue only goes up to DEC 29^o 16'

Some of the most distant galaxies in this image are more than 2 billion light years away from us. I targeted this area because of the interacting galaxies ngc 4922 in the upper part of the image. The tidal stream was just about visible in the captured data.

2 hours ago, StevieDvd said:

You are likely to say:

"Alexa, polar align and focus my scope on M42 and image for 4 hours. And don't forget to use the cloud removal filter"

And of course add "Please"  as bio AI appreciates good manners.

You forgot one thing. The future 'Alexa' will be customisable. Mine will say, with that typical Dirty Harry voice (yes, I'm old enough to remember that): "D'you feel lucky, punk? It sure looks mighty cloudy from where I stand."

On 11/04/2024 at 21:56, tomato said:

That's a very nice image. The only problem I see with it, and that touches on the problem with bought data, is that it lacks Ha. I haven't seen any other image of this target, but the blue arms with all their knots just scream H-alpha. And since this is from a bought set, where others have decided what to capture, you'll probably never get it. When we capture our own data, we get to decide the what and how. 

21 hours ago, M40 said:

how do you all get over this problem?

Live fast, die young, that's my motto.

7 hours ago, engstrom said:

I have all of them downloaded on an external usb hdd attached the pi. I am running all the devices from a powered hub and I’m within a few metres of my router (although I might try a powerline adapter to improve the downloads for online solving)

I run Ekos (StellarMate) off a 64 GB micro SD card which holds everything I need. For my 1 m fl scope and ASI294, I have all the index files down to 5.6 arc minutes (fov 66 x 45 arc minutes). Using the internal solver and off the micro SD card, plate solving is reliable and fast, the fist solve usually within a second or two, and next solves take about a second or less. But I do need to clear the mount model (in the mount tab of Ekos) about twice per imaging season. The last time I had poor solving performance, was when I used the ASI 174MM as imaging camera. This camera has a much smaller sensor (and larger pixels), giving a fov close to 0.5 degrees. I believe that fov does matter for the plate solving performance, especially when doing polar alignment.

Btw, powered (USB) hubs can be a problem. People who use them seem to prefer industry grade hubs, and not ordinary home/office hubs.

5 hours ago, engstrom said:

performance is so spotty/variable

Which index files do you have loaded? The recommendation is to go down to 10% of the fov, but if you have the space for it, it doesn't hurt to go lower. For me, that has been one of the causes for poor platesolving. Other causes for general poor performance are low power and poor wifi connection (I now only use my Pi with an ethernet cable).

20 hours ago, glafnazur said:

That's really nice 👍

2 hours ago, WolfieGlos said:

Superb image Wim.

Thank you, guys. Much appreciated.

This target needs no introduction. The image is a collaboration with @Firas. He collected the data with his ONTC 8" telescope and Moravian G2-8300 CCD camera, and did the preprocessing. I processed the masters.

data:

RGB: 50 + 30 + 20, 180 s exposures (5 hours total)

L: 171 180 s exposures (8.5 hours)

Processed in PixInsight.

The RGB data was a bit thin, but the XT-suite made it manageable.

58 minutes ago, pipnina said:

I look in mine and see rust

That doesn't sound good at all. Rust = moisture + particles, neither of which should be inside a camera.

11 hours ago, saac said:

what's Polaris

That's not because of having an observatory; that's because of the permacloud.

3 hours ago, Elp said:

or any metal

Including the metal casing of a computer. 

5 hours ago, Thalestris24 said:

Happy Easter everyone!

Happy Easter. And good luck with setting up/configuration.

I use a MeanWell 12V 150W power supply. Put it in a plastic box with 12V car outlets. Nowadays it's attached to the base of a pier in my observatory. It has worked well for almost 7 years now.

4 hours ago, Thalestris24 said:

Hi Again

I've been looking at the mini PC options you mention. The MEle  minis look attractive with Windows. In fact the Stellarmate X is obviously a MEle packaged with the Stellarmate OS etc. At least the MEle could be used for something else maybe. Using Windows also means being able to make use of familiar astro software. so that would be a plus. 

I was a bit concerned as the Stellarmate X doesn't have an external antenna. The MeLE PCG35 looks better but doesn't seem to available in the UK (at the moment, at least), tut! Oh well, I'll have to think about it will revisit after Easter!

Cheers

Louise

The StellarMate X is a fanless pc, as you already found out. There is also the StellarMate Pro, that has power outputs for various equipment and dew heaters. Unlike the ASIAIR, StellarMate is not limited to any particular vendor or equipment. But to be fair, I'm not a fan of the StellarMate app. Normally, I use a web browser connection to setup and monitor a sequence. It's easy and works on any operating system.

9 hours ago, Thalestris24 said:

I'm too old and impatient to tinker around much with other stuff.

Imho, any remote setup is going to require some tinkering and learning. But the technology is getting mature enough that the tinkering can be kept to a minimum. Also, the difference between Windows and Linux isn't much of an issue nowadays. When I started setting up a remote rig, there was no pre-installed and configured system, and installation required knowledge of Linux. Gina's various discussions on this forum are evidence of this. My latest installation (going from Ekos/Kstars, via Astroberry, to StellarMate) was a lot simpler with only needing to burn the system to a memory card and configuring it for my equipment.

4 hours ago, Thalestris24 said:

I tried out my wifi outside just with a Samsung phone, which is currently set to 2.4 GHz. It's a bit on the edge, and it cut out when I was downstairs but reconnected when I went outside. I was able to browse a bit on the net. It's from the second floor and through double glazing. It started raining so i cut my test short... I'll try again and maybe with the kitchen window ajar which might make a difference. I could also try moving the router closer to the kitchen.

I was a bit concerned as the Stellarmate X doesn't have an external antenna.

Wifi is going to be the weak link. The StellarMate pro (step up from the X) does have an external antenna, and it does have a hot spot mode. You might also consider a wifi antenna in your apartment. That might give you just enough signal for your setup. The advantage of a system on a fanless computer (Mele, StellarMate Pro, or Raspberry Pi) is that it is self contained. Once you've set up a sequence, it doesn't need further supervision. if the Wifi signal is lost, a sequence just keeps on going.

Nice to see you here again, Louise. After reading your op and some of the response, I'm still somewhat confused. You write that you're interested in the synscan wifi module to control your mount. With that a standalone autoguider. What will you use for camera control?

As an alternative to the Staraid, there are the Lacerta Mgen autoguider, the Skywatcher Synguider, and the Celestron Nexguide. (I have no personal experience with any of these, although I did look into the Lacerta many years ago.) The Lacerta is the more expensive option. Otoh it seems to have a better track record. It deserves to mention that it was the first autoguider to incorporate multi star guiding, even before PHD and Ekos.

There are other options for you. The easiest is the ASIAIR, but that is limited to certain equipment. Next are Stellarmate OS, and Astroberry. Both run off a Raspberry pi, and require a minimum of set up/tinkering.Any Raspberry Pi solution will require a 5V power source. StellarMate OS, including the app, costs about 50 $, while Astroberry is free, but lags in development. The StellarMate comes with an app that installs on an iPad or similar android device. Both can be used with a webreader such as chrome. There is also the StellarMate X, pre-installed on a fanless computer. This comes with internal power ports and dew heater outlets. Finally, you can have a small fanless pc, such as the Mele Quieter, with your setup, and run ASCOM on a windows machine.

The downside with all these solutions is that they require a stable wifi connection. Although, once you have set up your imaging sequence, they all run stand alone, if you want to. Of all the options mentioned, I only have experience with the StellarMate and Astroberry. Once set up, these systems just work, and keep on working, even if you lose the wifi connection.

Hope this helps.

10 hours ago, Fir Chlis said:

I’d also recommend getting a collimating cap (or make one),

The cheapest way:

SW newtonians come with a cheap 2× barlow. Unscrew the lower black ring that holds the optics. Drill a 1.5-2 mm hole in the very centre if the top cover. Voilà a budget collimation cap. Not the very best, but it will do for rough collimation.

Btw, if you have a laser collimator, use that with the barlow (with optics in place). The barlow will spread the laser beam, and you centre the shadow of the primary mirror's marker ring on the laser's bullseye. That's how I collimate my MakNewt. 

It has so far, only  been catalogued by the near infrared 2MASS survey. Since this is a NIR survey, it's of no surprise that it received the label "near infrared object". Most likely, no person (before you, Frank) has ever noticed it or taken a closer look at it. You could send your findings to either a local professional astronomer, or to a PN hunter like Marcel Drechsler or Dana Patchick.

A simbad search gives a link to a 1995 paper on the globular clusters near M81, but only as one of many data points in a graph. There's no further mention of it in that paper.

3 hours ago, tomato said:

106 galaxies

Nice! More than 1000 according to wikipedia, and 4291 registered entries in Simbad when you look up the Coma super cluster (but those may not all be unique entries).

4 minutes ago, gorann said:

I hope the motor arrive before the new moon !

Will be delivered on wednesday, so all is good.

5 hours ago, assouptro said:

Great capture, interesting target! 
Sorry to hear about your mount issues, I hope it’s resolved soon 

Thanks for sharing 😊

Bryan 

Thank you very much, Bryan. A new motor is on its way. I've only missed one clear night so far.

1 hour ago, AstroGS said:

I need to see how I can stretch further the image without clipping the core of the galaxies.

The stream is about brightness (luminance, if you will), while the background is about colour. There is no ifn, so you can keep the background fairly flat.

With this image, I would probably start by using a very strong dose of MMT on chrominance with a mask protecting the galaxies, on the RGB image, before stretching

As i wrote before, the luminance can be controlled by a combination of Histogram Transformation, Curves Transformation, and HDR compression (HDRMT).

I played around with the image you posted, and came up with this. Just a little more of the tidal stream (it's a jpeg, xisf would be better), but kept detail in the galaxies. No work on the background.

in the mean time, it's a clear night 😏

That may very well all be, but I don't want to blow out my mount's motherboard, testing. Better safe than sorry.

23 minutes ago, pipnina said:

The number of bars on the rotor shows you the step angle. A 1.8 degree motor will have 100 bars on the stator and 98(IIRC) on the rotor. A 0.9 deg motor will have twice as many.

Yours certainly looks like an 1.8 to me

6 bars per coil on the stator, which has 8 coils, and 2 x 50 on the rotor

15 minutes ago, vlaiv said:

Yep, two more things might give a clue. AZ-EQ6 was in production before 0.9 degree steppers were common place, and this as well:

EQ mod prerequisites page shows that worm is 180:1, then total reduction is 720:1 (belted part is 4:1). There is 51200 micro steps per worm revolution. That includes 4:1 belt reduction and steps from stepper motor.

51200 / 4 = 12800 micro steps
AZ EQ6 uses 64 micro steps

12800 / 64 = 200 and that is of course 1.8 degrees since 360/200 = 1.8.

Thanks, both.

Vlaiv, I got the same information from the EQ5/EQ6 group on facebook.

Besides the number of steps and the torque, there is also a difference in the phase resistance, and with that the current draw. There are low current versions and high current versions of most stepper motors, as well as 5V and 12V versions. The motor in the mount is 12V, but since a model number is missing, it may be either low resistance (high current) or high resistance (low current). I measured a resistance between connections of about 6 - 8 Ohms. Not very conclusive, since the phase resistance also depends on how the phases are wired internally.