AstroMuni

7 minutes ago, Dedanann said:

the scope is only a 130/650 (and most likely not really 650 as the tube is slightly shorter, so thus the focal length will be slightly shorter too, but that's good for AP no?) 

if its the 130pds then the FL is very close to 650. The shorter tube is just to allow cameras enough room to reach focus.

8 hours ago, Dedanann said:

The Tracking is a Sky Watcher RA and Dec motor that seems to work very well, or at least, I think it does, but using live view on the camera shows the focus star drifting, usually to the east, and this makes me wonder if the motor control unit could be at fault, or is a worm/gear issue or is it merely drift?

In my experience I get trailing if I increase exposure beyond 30s without guiding on my HEQ5 pro. On some days I can get upto 60s but thats rare. So I am guessing that with decent polar alignment you should be able to get around 30s too. Try using a Y mask or a Bahtinov mask to improve focus and at a later point you could invest in a Coma corrector to improve the elongated stars in the corners. Good luck!

On 13/06/2023 at 20:15, Lotinsh said:

I haven't found any solution that would work for me on how to collimate the focuser.

There are a couple of alignment screws on the base of the focuser that allow you to adjust the angle. Is that what you are looking for?

5 hours ago, ollypenrice said:

I had this idea while working in a non-astronomical domain, but it concerns working with small, fiddly components which are easily lost, flicked onto the floor, etc. As well as putting them down in a vertical-sided tray, you can put a strip of double-sided tape on the floor of the tray and put items down on that to keep them secure.

Great idea. I line the bottom of the tray with coarse sponge and this allows me to arrange the small items in different positions to coordinate the sides I removed them from etc. It wont survive a bump but light nudges dont affect it. Turkish towels work as well.

On 18/06/2023 at 21:05, bomberbaz said:

I do have this ota on sale or return basis, so (weather permitting|) I have time to have a little play with it to ascertain if I can get anything worthwhile from it. 

I have used this OTA extensively and you can see a few images taken with this in my signature link. As to whether it has a spherical or parabolic mirror - I have no clue. But images of DSOs come out pretty decent I must say. Focuser is tricky to use manually as there is no fine focus and it can be wobbly as well.

EDIT: I even managed to attach the ASI533 pro to it (no coma corrector) and imaged these. So good luck and look forward to seeing your images 🙂

32 minutes ago, Peter Drew said:

Geometry suggests so.  If you draw an axial centre line and converging beams from the primary, cutting through the light cone at 45* shows that the cone radius is greater below the centre line of the diagonal than that above the centre line.  The "faster" the primary mirror is, the more this is exaggerated.     🙂

My understanding was it should be an ellipse (atleast serving from memory of good old orthogonal projections 🙂 ). Like this https://en.wikipedia.org/wiki/Conic_section#/media/File:Conic_Sections.svg

Am I missing something here?

3 hours ago, Peter Drew said:

Ideally, a Newtonian secondary should be pear shaped

Sorry, didnt understand this. Can you explain please?

On 27/05/2023 at 17:04, Mikey0368 said:

is there a better option out there that I should look at?

Heres another way to look at the problem - which scope works best with the camera(s) that you have. If you put your camera details into the astronomy tools calculator you can play around with changing the focal length and binning to get a range of focal lengths that are optimal. This way you may actually end up spending a lot less and getting an additional scope instead of additional camera 🙂

I found this software which works on your android phone and allows you to control your INDI devices from it. It seems to have features to control the mount, camera and use PHD2.

Has anyone tried and used this?

On 07/06/2023 at 09:07, johnturley said:

I've never had to re-collimate the primary, just the secondary.

You would hope its the other way around as the secondary is harder to collimate 😞

On 11/06/2023 at 15:27, Albir phil said:

So I aske,at what point on our climb up the hill do we suddenly become a. "real imagers" or a real driver etc etc.I don't think we never stop learning 🤔🤔

I think you have said it in a nutshell - we never stop learning! Book or no book....a lot of the stuff that I learnt as a student is either out of date or more new discoveries have been made. Just in the last few years software like NINA, Kstars, Siril and several others have come along and are now taking over from the established software products of the past. CMOS cameras are changing the way we image as compared to CCD. So its all about keeping up with change 🙂

Have you looked at the ASIAir ?

To add another grenade 🙂 ...if you are a Mac/Linux/RPi user you could use Kstars/Ekos for planning and control. If you are a windows user you could use it for planning. You can tailor the planetarium to look plain or add the full DSS map view.

55 minutes ago, Mognet said:

Thanks. I haven't used a filter. I suspect either my focus was a little off, or I'm stretching the data too hard as the exposures may not be long enough. I've attached one of the subs in FITS format, and the stars look fairly sharply defined in that

Thats a great start...As others have said try adding a UV/IR cut filter and see if you can reduce the FWHM on the stars to improve focus. The aim is to get lowest FWHM ie. sharpest stars. 🙂 Good luck.

7 hours ago, Kiwi_Brad said:

I am outside it’s backspacing and with a DSLR I can’t get any mess with my OAG

Where in the train is your OAG? If you put OAG first thing after the scope and then CC, DSLR you should be able to get backfocus is my guess?? Guiding doesnt need coma free stars

9 hours ago, Kiwi_Brad said:

this image is the centre of the fov

The overall image is looking much better. I think the reason for the oval shapes in the left hand side is a combination of tilt and collimation. If you are getting similar ovals on the right hand side which are like mirror images of the ones on the left then you will also need to look at adding or remover a spacer between CC and camera. 

And as alacant says, take a look at your processed images and decide if you still wish to improve it.

I suspect the circle is as a result of a combination of focuser tube being too far inside (as vlaiv said) and the fact that you are now capturing the image thro a 2". In the 1.25" image this circle would still have been there but closer to the edges.

On 22/05/2023 at 19:49, MessierMatt said:

Untracked, Skywatcher 150p explorer, 291 lights at 0.6s, no darks or bias, Canon 800d. 
Loving the challenge and results. 

Lovely image for an untracked mount. You should be proud of yourself 👍

4 hours ago, powerlord said:

thanks Guy, it was shot with my 300PDS though - not an SCT. Think Iraqi supergun 🙂

Very nice image 👍

On 30/05/2023 at 09:55, Kiwi_Brad said:

The two images are both of the southern pin wheel and a single frame.  Different exposures but you can see the differences in the images.  The second image is using the L-enhance filter.  I have a pds130. Eq6-r mount and use a Nikon DSLR

I would suggest taking images where the stars are slightly out of focus so you can see if its collimated properly. Its tricky to get the back focus distance correctly and it took me a multiple tries to achieve a situation where I was happy with it. Also worth checking the tilt as I struggle with getting the camera+CC perfectly in line with the focal plane. Have you upgraded the eyepiece clamp to a compression ring one so that this can be better addressed?

On 26/05/2023 at 16:57, labtech1122 said:

When I go into photometric colour calibration and search for the NGC object it doesn't come up with anything.

There could be a couple of reasons for that - no internet connection, the provider's server (eg SIMBAD) is down. Otherwise I havent had any such issues

As long as Astroberry relies solely on one person to take it to the next stage then we have a potential problem. IMO it should be a collaborative effort. So lets hope there are others out there who can help push Astroberry onto the 64bit space.

16 hours ago, vlaiv said:

This brings on an interesting topic - how many galaxies can be actually seen with a naked eye?

We could include our own as we can see the core 🙂 And we can see a few nebulae too eg M42

On 28/05/2023 at 12:46, Ravi Hegde said:

For visual astronomy, which scope performs better? 130mm reflector or 102mm refractor?

One aspect thats also important is the mount. Get the sturdiest mount that you can afford. Generally the stock mounts supplied with these scopes are its weakest link.

On 28/05/2023 at 15:24, SwiMatt said:

how much work is collimation really? So much has been written about it on the internet, but somehow it's still unclear to me. Especially in the beginning, when one is still learning, I'm afraid it could be so offputting that I would end up not observing at all.

Dont be put off by it...heres the good part..if you are not collimated perfectly, its still OK. All it means is the scope is not making full use of the optics. The chance that your scope is delivered to you badly out of collimation is low so you should be able to make a start. If you are seeing stars with strange shapes other than round then you know you need to collimate.

Learning to collimate is a bit like learning to drive a car, initially it seems hard and confusing but in a couple of days it seems routine. And once collimated, you may just need to tweak it once in a while to make sure its still aligned.