bosun21

I also bought and sold a 6" CC for the same reasons highlighted above. This time I bought the 180 Maksutov which is proving to be very good on doubles with very near apo refractor performance. The small CO contributes to this I'm sure as well as good contrast.

I had difficulty connecting to my PC with my dobsonian using the V5 handset. My AZ-EQ6 connected easily but not my Synscan dobsonian. I ended up using the WiFi signal to connect to the Synscan app on my PC and then use the Synscan app driver to connect it to everything else via ASCOM including Stellarium. Have you downloaded the ASCOM software?

7 minutes ago, IB20 said:

I’ve had it more with refractors than reflectors. Currently on a 5” after starting at 3, then 4”. Who knows where I’ll end up?! 😅

Bankrupt probably 😂.

I also used to gaze up at the night sky and just let my mind wander. After many years I am still waiting for it to return.

You could I suppose fit a thin flat bridging plate between the forks and fit a vixen saddle to the centre of it. This will at least allow you to attach a smaller telescope to the saddle and still retain all the functions and benefits of a driven/tracking mount. Good luck.

Is your dobsonian one of the newer models with WiFi? If so it's pretty straightforward as I have recently done just this with my 10" Synscan dobsonian.

4 hours ago, PeterC65 said:

While they are seeing little use over the Summer, I've been modifying my two Newtonian scopes (Explorer 150PDS and Explorer 200PDS). First up is the addition of fans, mainly to get warm air flow to the secondary to prevent dew, warmed by the primary dew heater. Here are the finished results ...

Explorer 150PDS

Explorer 200PDS

I started by purchasing 3mm thick plastic disc from PlasticSheets.com. The ones I bought are black matt Perspex, and you can get them cut as circles (and other shapes) to a specific size, so I measured the diameter of the inner part of the mirror holder for both scopes and ordered this size. The discs come covered with a plastic film and to this I glued a piece of paper so that I could mark out the holes that I needed. I cut the holes mostly with wood cutting twist bits (the lip and spur type), using a Forstner bit for the larger collimation adjustment screws and a tank cutter for the central hole (in both cases, cutting the holes from both sides of the plastic sheet). You do need to support the plastic on a flat block of wood to prevent the twist bits from breaking out. Here are the plastic baffle disc with the required cut-outs ...

The fans I used are Noctua NF-R8 redux-1200, purchased from Amazon. They are low noise but with sufficient air flow from what I've read online. There are three connections, red is 12V, black is ground, and yellow is a speed control which is not required. I connected the red and black to a chassis phono socket fitted into the plastic disc to allow the fans to be powered from my dew heater supply, via a phono to phono cable. I then attached some double sided tape to the inside of the plastic disc to fix them to the scopes. Here they are just before assembly to the scopes ...

Hopefully this will keep dew at bay from the secondary during my long Winter EAA sessions.

My next modification is to change the spiders, improve the collimation adjusters, and fit covers to the secondary mirrors to further reduce the chances of dew.

 

Nice neat job Peter, and well documented 👍.

2 minutes ago, geoflewis said:

Thanks Ian, I was a little disappointed, but note that it's been given a north up orientation, so whilst I haven't checked I suspect that all the images may be displayed the same way. Also the Mira variable V720 Ophiuchi has been highlighted, with reference to it being found just 9' south of the main star cluster, so orientation is important for that reference.

That makes good sense and is more than likely why they changed it. I still liked seeing the crucifix though.

21 minutes ago, geoflewis said:

I just received a complimentary copy of this new atlas from Cambridge University Press (CUP). I was contacted a couple of years ago by the author Ronald Stoyan, who asked me whether he could use my version of M107 in the revision (2nd Edition) he was producing. I of course said yes and am delighted to see its inclusion.

My original version may be seen on my astrobin page here. The image in the 'Atlas' has been cropped and rotated about 90°, so it's lost the crucifix appearance as I displayed it, but I'm still pleased to have one of my images published.

The atlas itself is an excellent, large hard copy publication about twice the size of my iPad. As well as colour photos of each Messier object alongside pertinent notes, there are are also some 60 pages of introductory notes covering not only Charles Messier and the creation of his catalogue, but references to other prior and subsequent observers and their observation notes and lists, including an introduction to the Herschel 100.

If you want your own copy the Atlas is now available from many of the usual book retailers as well as direct from CUP - UK prices range from ~£50-£60.

Lovely image of M107 on your Astrobin. The crucifix aspect is easily discerned and I wonder why they decided to rotate the image.

From your description it suggests that something is wrong with them. The images from them should be very similar to your other other pair of 10x50's from the same manufacturer (Opticron). If they are as bad as you say then I would return them.

32 minutes ago, Alan White said:

As an update.
Having now used the SL20mm in my Reflectors and Refractor, I can offer my feelings.
Flipping Brilliant is the short version!

I can manage the whole field, but my glasses are pushed firmly to the EP to do this, but not rammed up against.
The images I am seeing in multiple scopes are all similar and all excellent.
The stars and colours are very obvious and the subtle nebulosity at times is obvious.
This compares well to my 30mm APM UFF and Morpheus 12 and Pentax XW etc.
It just sits right in the pack and does not stand out, very similar focal point to the Morpheus and the SL30, a bit different to the XW's by a little.

Highly recommend this one, its a hidden Gem.

OK this is not a scientific test and just my experienced observing eye across my scopes, 
take it for what it's worth, but somehow I doubt it will disappoint if you have a similar stable of glass to myself.

What f ratio are your scopes please Alan? I was actually looking at this range of eyepieces.

5 hours ago, bosun21 said:

It’s interesting though as I found a CN thread saying most recent gso dons do not require this mod

The newer GSO dobsonians definitely do require the mod if you want to have fine adjustments available for the secondary mirror holder. In fact the GSO (Stella Lyra) dobsonians require the mod even more so than the Skywatcher scopes. The former having much deeper indentations on the holder which prevents fine adjustments.

Having owned quite a few Newtonians over the years I was never bothered nor really noticed diffraction spikes. However after reading a few threads on the question I now do indeed notice them, and find myself actively looking for them. This was one of the reasons I bought a 180 Maksutov for high magnification planetary observing minus the diffraction spikes. I now primarily use my 10" Synscan dobsonian for observing everything else where they are far less noticeable. Planetary imaging however isn't really affected by diffraction spikes as far as I have noticed so the 10" dobsonian can redeem itself in this regard. Love them or loathe them it's a penalty we pay.

1 minute ago, DAT said:

Seems like it’s best to take the  secondary out and measure everything then. I will also make sure the washer is about the same size as the holder as the screws are close to the edge. My only other question is does the central whole need to be big enough for the screw and the spring or just the screw? Looking at all the pictures I can’t see why either way would not be ok.

It’s interesting though as I found a CN thread saying most recent gso dons do not require this mod. It’s definitely more a “challenge” than a necessity for me, hopefully it will make the collimation process easier to understand .

Thanks for all the replies

Just the screw 👍.

10 hours ago, DAT said:

Do you by any chance know the size of the washers you used?, both the outside diameter (I think it should be 43mm--44mm) and the inside (5mm-6mm?). I am struggling to find and exact fit but maybe that is not so important...

The scope that I bought the washers for unfortunately is a Skywatcher 10" Flextube Synscan dobsonian which has a completely different secondary mirror holder. I have carried out the mod to two Stella Lyra dobsonians as well. One was an 8" and the other a 12". As long as the washer is smaller than the diameter of the secondary mirror and that the centre hole is large enough for the central screw.

On 26/05/2024 at 22:20, John said:

One of the key points that Don makes (and more than once) is the importance of dark adaptation and staying dark adapted when searching out fainter targets. I can recall just how much trouble I went to in that respect when I managed to first see the Horsehead Nebula from my backyard a while back with my 12 inch scope. I think I went for 2 hours without looking at any sort of light - even the reticule in my Quickfinder was turned off in case I got a glimpse of it !

Another good point that Don makes at the end of the movie is aimed at those who are starting out. He says that you will never see less than you do now if you keep at it. Which is very true - practice tunes the eye and brain to see and much of what is "learned" during one session returns quite quickly at the next one so you start from a better, more experienced place.

The point made by @Space Hopper about limited opportunities to develop these skills, especially in the UK perhaps, is valid though 🙄

 

I totally agree with you regarding being dark adapted properly and that the art of observing is very much a learned experience. I do also think that spending longer periods at the eyepiece is very conducive to learning the skill. For instance last week during the first light outing for my 180 Mak I spent about 30 minutes observing M13 at the eyepiece hooded for each eyepiece. The longer I observed using both direct and averted vision the more details were being slowly revealed to me. In fact details that at first were only visible with averted vision were slowly becoming visible to direct vision. Anyway that's my ramble for this evening.

The Celestron 0.63 reducer is not suitable for Edge SCT's apparently? This is what some suppliers are indicating.

I always carry out this modification to every dobsonian I've owned. Last time I just bought ten plain washers from eBay and sprayed them matt black. This mod eliminates any stiction when positioning the secondary mirror holder and has worked great every time.

Beautiful image and great processing. I have never attempted a mosaic before. Perhaps I should start considering them and read up on their procedure.

The Stellarium mobile and PC app are not the same.

Good to hear a conversation between two amateur astronomers where the word imaging was never mentioned. If only the gasoline filter was more practical for us to use much more often. Thanks for bringing this to our attention @Nik271.

"Welcome back James" it is James I presume?

The more recent models have the USB port and can connect to your PC or ASIAIR with just a straightforward USB A to B cable. I have connected several mounts to my PC and AIRS with zero problems. This eliminates the need for an EQDIR cable.

I use an AZ-EQ6 mount on its 2" Stainless steel tripod. I know that it's a heavy mount but I don't mind as I love it for high magnification planetary observing and imaging. I will be adding a > 120mm apo refractor shortly to my kit so I will be needing a pier extension for it. I am also intending to purchase a Berlebach tripod for it , probably either a Planet or Uni. I much prefer EQ mounts although the alt/az setup of my 10" Synscan dobsonian is growing on me.

9 minutes ago, John said:

My OO 12 inch F/5.3 was about 17kg inc accessories. Aluminium tube. 

 

The O Optics aluminium tubes do appeal to me. I was considering buying a 10 or 12" OTA when one of each size were recently advertised in the classified section. I was thinking of putting it on my AZ-EQ6. I then realised that this would be pointless as I already had a 10" Synscan dob. I really do need to keep myself in check when browsing the for sale astro sections!