DKNicholson

It is difficult to know which comments are causing confusion, but I'll take a few guesses! 🙂 (1) A 'dob' is short for Dobsonian and in basic concept it is of a similar type of telescope to the Celestron PS1000 - they are reflectors. Dobsonians normally sit in a wooden 'cradle' that sits on the floor, whereas Newtonians normally sit on a 'mount' on a tripod. They are both known as reflectors because the light comes in through the open front and goes down to a curved (concave) mirror which reflects the light back up the tube to another very small mirror set at 45 degrees. This one redirects the light to a viewer/eyepiece that sticks out of the side of the tube. (2) Refractors are the traditional style of telescope that have lenses at the front that focus the light to the bottom of the tube where the eyepiece sits. These lenses can be expensive to make and cheap refractors have only a small aperture at the front. Mirrors are cheaper to make because they do not rely on high quality glass for lenses. (3) The aperture. The bigger the hole at the front of the telescope (the aperture) the more light is collected and focused to the eyepiece. Whilst stars are relatively bright and require very little aperture to be seen, some deep sky objects are very faint and require a large aperture to collect more light so there's a greater chance of seeing them. Dobsonians (dobs) are the best value for money when it comes to aperture because the money goes in to making the telescope and not the mount that holds it. Olly Penrice suggests the SkyWatcher Skyliner 150P and if anyone knows what he's saying it's Olly Penrice! 🙂 This telescope has a 150mm aperture and would be a very good starting point. I can find very little information on the Celestron PS1000, apparently it has a 127mm aperture (but generally not a recommended telescope). A 200mm aperture reflector would be even better than 150mm but it also becomes more awkward and heavier to carry. With a simple Dodsonian there are no directional adjusters, you basically push the telescope around on a low friction 'cradle'. This is not such a problem once you know your way around the sky, but you always have to nudge it to keep it looking at your chosen object - the Earth's rotation is the issue there. Newtonians are normally mounted on an EQ - equatorial - mount that has manual adjusters to move the telescope up/down and left/right. With Dobsonians/Newtonians it may be necessary once in a while to check the alignment of the mirrors, this is known as collimation - not really an issue with refractor telescopes. All telescopes need eyepieces to look through in order to see whatever it's pointing at. Usually they will come with one or two and it is necessary to ensure this is the case or you will have to buy at least one - 24mm is standard and cost somewhere around £30 for an inexpensive one. The telescope should also come with what is known as a finderscope. This is normally a very small secondary refractor telescope that you use to look through when trying to point the main telescope in the right direction for the chosen object. Olly Penrice mentions Stellarium and it is a free piece of software for either PC/laptop or smartphone and it shows a detailed view of the night sky - what's out there and where to find it. Finally I should mention 'GoTo' telescope mounts. These are computerised mounts that point the telescope at an object selected by you; they are the astronomy equivalent of vehicle SatNav. The SkyWatcher Explorer 130P ( https://www.firstlightoptics.com/az-goto/skywatcher-explorer-130p-synscan-az-goto.html ) is a good example of one and would be a good starting point, but it's £325 - but if you can stretch to that it would be much easier to use. I do hope that some of this helps just a little and I wish you all the best and a Happy Christmas

OK - here we have my latest and greatest observatory set-up! 😄 The red signature 'scope is a William Optics GTF81 that has spent the last 3 years in my garage doing nothing. Then last night I had an epiphany - why not add it to the Altair Wave Series 115 and put the TS-50 guide 'scope on top of it! That way I can utilise the GTF81 without having to dismantle and store the 115 - I just have to swap the camera and filter wheel over! It has taken so long to think of this as the mount is now an SW EQ6-R Pro, up from an HEQ5 Pro Synscan, and until recently I have been using an SW ST80 for guiding which was way too bulky for this set-up. Hopefully the load will not be too much for the mount as vibration may be an issue - just have to see! Don't you think the Altair Blue clamps and mounting plates are truly excellent - sadly now discontinued!

I know that it's never nice to spend money if there's a cheaper alternative, but under the circumstances I should be inclined to bite the bullet and buy something like a QHY5-II that has been specifically designed for the purpose of guiding. It will also probably be quite a bit more sensitive enabling greater probability of finding a suitable guide star. Just a thought.

Imaged over three evenings but only just over eight hours integration (weather . . . !) with Flats and BIAS frames added. Taken using my spangly new Starlight Xpress Trius Pro SX694 CCD camera. Telescope: Altair Wave Series 115mm - Camera: As above - Filter Wheel: Starlight Xpress SX-USB - Filters: Baader Ha, SII, OIII - Guided by: SX Lodestar x2 on a TS-50mm - Mount: SW EQ6-R Pro - Capture Software: SGPro with PHD2 and Platesolve2 - Process Software: DSS, Nebulosity V4, Photoshop CS3

I have this thing for Saturn and I have many videos I've taken over the years. This image is the result of one I took in July this year that I hadn't taken much time to process. It is 20% of 2,000 frames taken on a ZWO ASI120MC through my Meade LX90-8".

Thought I'd try something a little different - NGC7129 - Reflection Nebula and NGC7142 - Open Cluster. LRGB about an hour of each, but the nebulosity was surprisingly faint so took a fair bit of difficult processing. Telescope: Altair Wave Series 115mm (very highly recommended - nice Christmas present! BTW - I have no business interest, I just really like the telescope!) Camera: Starlight Xpress Trius Pro 694 Guiding: Lodestar x2 through TS-50mm Mount: SkyWatcher EQ6-R

Using a 2" Antares x1.6 Barlow into a 1.25" filterwheel then camera, curiously led to noticeable vignetting where I had hoped it would help avoid it. So whether the vignetting was a result of that particular Barlow or just an inevitable result of using a Barlow, I don't know, but it is perhaps something to watch out for.

Have you checked how far past the meridian your system will go before it attacks the pier? If it is more than 20 minutes or so then try setting the meridian flip for as late after the Meridian as is reasonable. There is also a setting in PHD2 to reverse the guide camera after the flip though I have never found the need to tick that as it seems to do it automatically. I wish you luck as this sort of error can be so frustrating. Yours aye . . .

Copernicus through Meade LX90-8" onto a ZWO ASI120MC using Sharpcap. 20% of 3,000 frames processed using Autostakkert-3, Registax-6 and Photoshop CS3.

Impressive image - very nice.

This may be a useful article - http://www.wilmslowastro.com/tips/autoguiding.htm and also this calculator - https://astronomy.tools/calculators/guidescope_suitability

The main issue I encountered was quite severe vignetting even with the 2in Barlow through 1.25in filters onto the small chip of the Atik. Using the Trius I think it would not be acceptable at all. When I can be bothered to mount it I have a Meade LX90-8" for very small DSOs, but I'll do with the 115 for a while until I get used to the camera.

There were quite a number of issues with this image. The dust bunnies on the camera screen obscured some of the subtle detail - for some reason I had failed to clean the screen before installing. As a consequence the flats struggled. Also I have been using an Atik 314L+ for the last 8 years so I have yet to become used-to the requirements of this camera - it's very different. The integration time was not only too short but also affected by high, thin cloud for much of the time, so DSS showed that some of the frames were not of the best quality. Altogether it was quite frustrating as I have had the camera for three weeks now and have only managed 4hrs 35mins in that period. Whilst it is fairly basic and far from perfect, the attached image is what I managed to achieve with the Atik through the same telescope but also with a 2" Antares Barlow x1.6 in the light path that I had been experimenting with. Not a huge success it has to be said, but I may revisit it in due course.

This is the first object I've been able to image using my nice new camera - Starlight Xpress Trius Pro 694. It's not ideal and I plainly have a few things to learn before I can get the best from it, but I'm not too unhappy with this as a starting point! The total integration was just 4hrs 35mins, and with the weather we've been having I was lucky to manage that! DSO: NGC7023 - The Iris Nebula Telescope: Altair Wave Series 115mm Camera: Starlight Xpress Trius Pro 694 Filter Wheel: Starlight Xpress with Baader LRGB filters Guide Telescope: SW ST80 Guide Camera: Starlight Xpress Lodestar x2 Mount: SW EQ6-R Pro Software: SGPro, DSS, Nebulosity V4 (for alignment), Photoshop CS3