John

With your scopes the Skywatcher Aero ED 30mm would work pretty well. I have the 30mm and 40mm in that range which I find very good with my refractors of F/6.5 and slower. I do use Tele Vue's with my 12 inch F/5.3 dobsonian though. It's well worth watching the used market though - the Aero ED's can be had for around 50% of the new price in nice condition. Tele Vue's tend to commant somehwat more. There are also good wide angle eyepiece ranges from Explore Scientific and some other brands which can be had for substantially less than Tele Vue prices. I was a bit disappointed with the Baader Hyperion Aspheric though, for it's price. Too much outer field astigmatism even at F/8 for my tastes.

I guess it depends how faint the stars are that you are going to use as hopping points to your target. If you are looking for something moderately faint then even a large aperture finder is not going to show it - thats what the main scope is for after all. When I'm going for really challenging and faint targets the main scope with a low power eyepiece forms part of the finding system: - Illuminated reticule finder: gets me to within a couple of degrees of the target - Optical RACI finder: used with a good star atlas to get closer, to around half a degree of the target location. With targets brighter than mag 10 the optical finder can pinpoint "suspects" as well. - Low power / wide field eyepiece in the main scope: final stages of star hopping using fainter stars and confiming (or otherwise) "suspects" Thats my approach anyway. I think thats the thing with finder systems - each person develops a method that works for them and then supports that with suitable finding devices.

Having 12 inches of aperture did move me into a different area of observing when I made that change I felt. 10 inches was very nice but somehow a foot of aperture opens up the deep sky to the extent that you feel that you can really get in amongst the NGC's and also have the capacity make the M's much more interesting. Very unscientific I know but my 12 inch dob has shown me some of the best sights that I've seen in this hobby I've looked through Flextubes but I've not owned one so I'll let others comment in detail about the pros and cons of that particular route to aperture. The ones I've used seemed pretty competant to me though.

Are you able / prepared to use 2 inch eyepieces in both scopes ?

As has already been suggested, the ideal setup is to have both a Rigel / Telrad and an optical finder on a scope - they complement each other.

If it is just a bit dusty it probably won't affect it's performance much. If it is really dirty the following procedure is the one that I use: https://www.skyatnightmagazine.com/advice/how-to-clean-a-reflector/ Some optical cleaning fluids (eg: the Baader Wonder Fluid) are not intended for use on aluminised surfaces.

Depends if it has the collimatable objective cell or not. The collimatable cell adds fair bit to the overall weight and makes the scope somewhat top end heavy. I've owned both types and I seem to recall that they came in at around 9kg - 10kg depending on the cell design. That would include tube rings, a dovetail bar and the finder and diagonal. I'm talking about the F/8 ones here. If you are looking at matching to a mount remember that the tube length with the F/8's presents more of a challenge to a mount that it's weight.

I have 3 of the RACI Skywatchers so they do exist. The key is the shape of the prism housing - the RACI ones have a cut off shape wheras the inverting (but not RACI) type have a full diagonal shaped prism housing. Pics to illustrate: RACI: Inverted image but non-RACI:

Yep, I'm all for the "Telescope House shop floor in the 1980's" look but my other half has other ideas

I have a dining / astro room as well. Currently it's housing 4 mounts 5 refactors, 2 cases of eyepieces and a 12 inch dob. Plus we are trying to re-decorate it ......

It's pretty good here. I've packed the scope in but just popped out with some 8x30 binoculars and found M33 quite easily.

Tonights session with my 130mm refractor was supposed to be all about testing the Rowan AZ100 mount really so most of the time I was observing targets that needed high power such as double stars, Neptune and Uranus. While in the Aries / Pisces region of the sky, having found Uranus, just as a break I popped the 24mm Panoptic in the scope diagonal and had a lower power browse. I was rather pleased to be able to pick up the faint glow of the core of the face-on spiral galaxy Messier 74 near the star Eta Piscium. This galaxy is 32 million light years away and considered a classic example of a grand design spiral galaxy. It is also however known as the "Phantom Galaxy" because of it's reputation for being quite hard to spot in moderate to small aperture scopes. One of the harder Messier objects I understand. Anyway, I was pleased to find it with the 5.1 inch refractor. I'm fairly sure that I've seen it with my 12 inch dobsonian but that gulps a lot more light than the frac !

I use 6x30 RACI finders with my refractors up to 120mm aperture. For my 130mm refractor and my 12 inch dobsonian I use 9x50 RACI's. Alongside the optical finder on the dob I use a Rigel Quickfinder illuminated reticule finder. I have another couple of illuminated reticule type finders that I can use on the other scopes if the intended target makes that sort of finder more useful. I'm often on the flight path for Bristol airport so I would not use a laser sight. We use one at my society outreach events but very sparingly.

Clear patch

Grrrr .......

I've seen those in medieval kitchens, usually with a leg of lamb or pork hanging from them !

It is not completely balancing the weight of the scope but I figure that it would be reducing the effective imbalance, hopefully to the extent that the mount should be comfortable with it. The scope weighs around 9.5kg and the weight is 5.2 kg. Testing under the stars should reveal more about the extent to which the scope weight needs to be fully counterbalanced across the altitude axis. I do have some other counterweights but not in the 25mm fitting that the AZ100 uses so I will have to come up with a method of hanging them from the C/W bar alongside the Rowan weight - I'll look out a suitable bag of some sort

I'm hoping for some clear skies tonight to give the Rowan AZ100 a run out with my 130mm triplet refractor on board. Since setting the scope and mount up blue skies have been replaced with a cloud layer but perhaps that will give way to something better in due course. While I wait for darkness, here are some more photos of the mount. This mount head has been upgraded by Rowan to have what they term as damping knobs fitted to the altitude and azimuth axes. The purpose of these is to allow some adjustment to the mesh of the worm gears to obtain the smoothest motion when a heavy and potentially slightly imbalaced load is on board. The original mount head that I was sent has had the same modifications made and is now with @Stu for him to test in parallel with my own trials. The head pictured here does not have encoders fitted (hence the plates covering the openings in the body of the mount) because I will be testing the mount as a manual one. @Stu will be giving the Nexus Digital Setting Circles unit and the encoders a thorough work out during his tests. I must say that Dave at Rowan Astronomy has been really responsive to feedback that I've provided on the mount so far - thanks Dave Just to remind readers that the units that @Stu and I have are pre-production versions so there may still be small variations to the final product

I thought for a moment that the guys in the distance with the yellow hi-vis vests and hats on were working on your observatory !

The scope is OK but it's way undermounted in my opinion - the mount is about the equivalent of a Skywatcher EQ3-2 and the aluminum tripod is hopeless with such a scope on board. You would need to invest in a replacement mount and tripod which is going to add £200 or more to what you pay. overall. Now if you could get the scope tube alone for well under £100 and make a DIY dobsonian mount for it, you might have a lot of observing potential for very little outlay

This is a 9 year old thread.

Bristol Astronomical Society are holding a Telescope Surgery in the evening of Friday 22nd November. Those who are thinking of getting a scope or binoculars or those that have them but don't feel that they are getting much out of them are welcome to come along, with or without their equipment. There is no charge. A range of astronomy equipment will be present and Bristol AS members will be pleased to talk about their instruments. There will also be a short presentation introducing practical amateur astronomy and the range of equipment currently available. If anyone is interested please message me on this forum in the first instance so that I can give the Society some idea of numbers of potential attendees and equipment that might be bought along. The event will start at 7:00 pm and will take place at the Bristol Photographic Society, details at the top of this webpage: http://www.bristolastrosoc.org.uk/www/pages/resources/faq.php

Robin Hood and the merry men !

Fair point To get back to your original question, at the focal ratio that the 130 / 900 is operating at, I think a spherical figure will work fine. I've used one of these scopes (unmodified) and it performed pretty well for it's aperture on a wide range of targets.

I wonder if the FT dual speed addition has any side affect on the stability of the focuser ? I don't get sideways play with my R&P focusers - the tension on the grub screws on the top of the focuser pushes the drawtube onto the guiding strips / shims which seems to keep the drawtube from moving from side to side.