Clarkey

Welcome to SGL.

If you are looking to get into imaging, you don't want to be going any lighter than the AVX in my opinion. Probably a pretty good match with the ED80. By the time you have added the camera and other kit you will be close to 2/3 of the quoted capacity which is a good rule of thumb. Looking at the selection you have, it is a pretty good range for FL and types - although with the others the Astromaster is probably a bit redundant. But as you say, there is little resale value.

7 hours ago, wvrfish said:

Now I just need to sort the collimation

Don't sweat it. It's not as hard as it is hyped up to be.

Normally yes. I have the Stella Mira version with the 48 and 42mm reducers and the measurement is from the back of that.

The spacing is normally from the back of the flattener excluding the actual thread - so you will need about 37.5mm of spacers.

There are a few cheap and cheerful scopes on Astro buy and sell at the moment. There is a newly posted 80mm APO that might be worth considering. Also, a couple of Achro's

If you are just running the mount, either would probably be OK (although I suspect 2 amp would be close when slewing). I would go for the second option which should power the mount ok for the time you need. Tracking only, the mount probably only draws about 0.5 amps.

I would take the capacity with some scepticism. Also, the total output is only 2A which might be pushing it - slewing, plus tablet, plus camera + (dew heater?).  At full current draw (2A) you would probably only get a couple of hours out of this assuming it does not trip on high current. Personally, I would spend a bit more an get something a bit better.

Whatever it is, it's not coma. Either tilt as @vlaiv suggests or possibly a collimation issue. My money is on tilt. If you are using the standard focuser there is every likelyhood.

4 hours ago, Ratlet said:

If I were going to image a galaxy using a osc multi pass filter, would I be better or worse off getting a triband or dual band?

Neither for galaxies. These filters are for emission nebulae. You could add Ha using and Ha filte to a RGB image, but galaxies should be imaged in broadband.

Quad band and Tri band filters are very similar, but the quad is used where there is less light pollution as I covers a broader area of the spectrum. The names are a bit misleading really as both are actually dual band. It is just one covers Ha and Oiii plus H beta, the other covers Ha and Oiii, H beta and SII.

1 minute ago, RolandKol said:

Should I think of any kind of corrector

The RC8 works OK without - I think all of the images above were at native FL without a flattener. I think if you go for a much larger sensor you might need to get a flattener, but these were all with an ASI 1600mm so you should be fine. (I think the RC6 does need a flattener).

Just another point (looking at your set up), I did struggle a bit with the OAG due to odd star shapes - although this does appear to be a common problem. I use an ST80 for a guide scope and it does not seem to cause any flexing issues.

An older ED80 by the looks of it. £300 with the extra's is certainly not over the top in my opinion.

I have the StellaLyra (GSO) RC8 and use it for imaging and I have found it to be excellent. (Similar to the iOptron but there may be some differences - StellaLyra 8" f/8 M-LRS Ritchey-Chrétien Telescope OTA | First Light Optics). Personally, I think it is bargain for what you get when comparing with an SCT etc. Answering your questions in order:

1. It is a narrow FOV but excellent for smaller targets. Not really a planetary scope though, but good for galaxy imaging.

2. As long as your guiding is 1/2 your resolution you should be OK. With a binned 2x2 ASI1600 it would give you just under 1"/pixel which is probably more than your seeing can support anyway. So your mount should be OK. With the CCD47 you can reduce you FL to around 1200mm (or whatever you want within reason).

3. I cannot answer for the iOptron focuser, but the GSO one was OK - but I did swap mine for a Baader ST. Probably not essential depending how fussy you are and which auto focuser you use. There was some slight slippage but only during autofocus routines (and not enough to be a major problem).

4. Never had a problem with meridian flips. No evidence for mirror movement. Collimation is not as hard as most seem to suggest - and once collimated it hold really well.

5. Some images M51, Coma Cluster and Hickson 44 (Leo Quartet):

Ok - bit of an update. It turns out is not the wifi extender causing the problem, both PC's did some updates and this is what is preventing the wireless connection. They now won't connect anywhere in the house. So.....

In my wisdom, after trying multiple setting changes suggested online, I decided to go back to the last restore point. Now the PC will not boot or do anything, even trying safe mode etc. So I have just spent the last couple of hours re-installing Windows from scratch. Then I will need to do all the astro software. To say I am a bit pi**ed off is something of an understatement. I know Windows can be pretty poor, but this is bad even for Microsoft.

Let's just hope when it is all up and running again I can connect 😫

Until recently I was running my imaging rigs using a mini PC on the scope, over my standard house wifi. Anyway, over the last month or so I have built a new observatory, but unfortunately the wifi signal is not too good and now keeps dropping. To remedy this, I purchased a TP-Link powerline wifi extender. So now I have a very good wifi signal in the observatory and a LAN access point.

The trouble is I can no longer remote desktop into the mini PC's over wifi. If I plug in the ethernet cable they are fine. Both have an excellent wifi signal.

Obviously, this is something to do with a firewall setting or similar. However, I have tried multiple different setting changes without success. Has anyone had a similar problem - and did you come up with a solution? I am reasonably computer savvy - but this has got me a bit stumped.

I would have to echo @wimvb comments regarding the f4 scopes - unless you want to spend extra for a 'decent' one. I got the TS 6" for imaging and the MPCC I had was not up to the job, so I had to buy the aplanatic CC. (I know the specs say the MPCC should be OK - but reality showed otherwise). Also, the focuser sag made collimation very difficult - so I replaced with a Baader ST. After all the expense I was still not overly impressed as I had major problems with internal reflections from filters. After a couple of sessions I binned it and sold the extra's. Collimation was also tricky to get spot on. Overall, I wasted about £800. 

F5 is much more forgiving.

What is wrong with a widefield refractor? Simple, reliable and very portable?

I recently purchased one from @Notty but am yet to use it in anger due to cloud (and worse, it is a tiny bit too bit for my observatory). So there might be a second hand one for sale in the coming weeks☹️

I'm not convinced about 'portable', it is heavy and bulky. Maybe I am getting old.....

OK, so the DD1 will turn on/off with the mains. That is good to know.

2 minutes ago, scotty38 said:

There are plenty of 24hour timers with three pin sockets if that's all you need

Unfortunately it is not that simple. I purchased a dehumidifier with this in mind, but when it lost power it would not restart without me pressing the button. I want to check if I buy another it will work on a standard timer socket timer. 

On 14/09/2022 at 22:45, DeepSkyMan said:

Hi there I recently installed an EcoAir DD1 Mk5 dehumidifier in my Pulsar Observatory.  Looking for recommendations for scheduling.  I currently have the unit scheduled on between 05:00 and 09:00.  I’m thinking that in addition to this I should probably have the unit running during the evening as well.  Or… perhaps there are more optimal schedules?

I was just wondering how you scheduled it to run? Is it on a separate time switch? I am looking for a dehumidifier for my observatory, but I cannot find one with a daily timer.

It looks pretty good. If it was me I would reduce the step size even more - maybe 50. To be fair it won't do much, but it might give you a marginally better result. However, your error bars are so small I don't think it will do much. Try the same autofocus twice one as is and one at 50. See the result for real.

I think tracking with such a small chip will be tricky. Getting the RA motor will make things much easier.

If it makes you feel better, I have used my 200p with a 3x Barlow and couldn't even find Jupiter in the FOV☹️. That's with goto and tracking....

I don't do planets much these days😄 Stick to big stuff and plate solve.

That curve looks pretty good. My only comment would be that it is a very large range of the HFR for relatively few steps. Personally I would reduce the step size and increase the number of points to get the focus spot on. If the range is too big it can give slight errors.

I don't know how severely stretched that image is, but I am not sure 'zero' really exists. However, that does look like a pretty clear 'glow'. I assume there was absolutely no light leakage possible?

1 hour ago, alacant said:

But hey, you've a relatively good example, so our initial recommendation remains: leave it as it is;

I would agree. The ED80 is quite good optically, but the focuser is barely acceptable. If you are having to pixel peep to see the problems - probably best left alone.

I would have to agree with the other comments. 20mm of aperture on a small scope is pretty significant. You might get a little CA, but given the difference in focal ratio I suspect it will be no worse than the others. At F5.5, even with FPL 53 will be pushing the limits. F7 of the ED80 is much more manageable.

What about the SW ED80 ds pro which I assume is still available? No idea on the NZ price though.