NGC 1502

Welcome to SGL👍 If you’re interested in joining a club you have several choices in Essex. Your nearest 2 are the N.Essex Society or my own club near Rayleigh- Castle Point AC.

Your best bet is to move much closer to the book😁 Perhaps a more useful answer- The best definition at the lowest price will be given by a Newtonian reflector. A 6” or 8” Dobsonian reflector is stunningly good value. If it’s to be your only scope then it’s worth paying the extra for the 8”.

Thanks for this, indeed great value compared with what was available many years ago. It’s easy to overlook what a small scope can do especially if the user is determined. (Deliberate repeat- if the user is determined!). My main scope is a 10” Dob. And yet my 105mm f4.2 Edmund Astroscan is a very useful little scope. With my 22mm Vixen LVW it gives a nice 3 degree view at 20x. Even from my light polluted back yard it’s a delight to scan the skies. Areas of the sky that reveal nothing to the unaided eye come alive with star filled views. Many brighter Messiers can be seen, wide double stars, a few galaxies, one or two planetary nebulae…… And with my 6mm Vixen LV at 74x Jupiter with the main cloud belts and 4 moons, a tiny Saturn, the globe with faint cloud bands, the ring system resolved from the globe and the shadow of the globe on the rings just discernible…and Titan too… Either of those 2 scopes from FLO could provide years of fun, such great value. Thanks to Steve for posting 👍

Enjoyed your report👍 Whilst viewing M103 there’s a curious open cluster a very short star hop away. This object is Trumpler 1. Visually it’s tiny and appears as a line of faint stars. It’s recognisable at low power but looks better at medium and even high power 150-200x. Definitely worth checking out😊

I just love Sheringham. I am not envious. I am VERY envious😊

I used to attend Kelling star party, between Holt and Sheringham. One of my most memorable nights was viewing through a clubmates TeleVue NP101 with a 31mm Nagler. Under the dark transparent sky I was blown away by the views. I could hardly believe the fabulous view was given by a premium 4 inch scope. So with your Tak FC-100 I would get a very low power wide field eyepiece. I’d also want a good nebula filter. A top refractor is very versatile, very low power wide field, to high power planetary and double stars. Enjoy your excellent scope under those excellent skies that Norfolk can offer👍 Ed.

I use Vixen/Synta dovetails myself. I’ve never been entirely happy with them, but not had the misfortune to have a disaster. It’s not difficult to fit a stop bolt protruding from the dovetail immediately above where it clamps onto the mount. Whilst not a complete solution it does add a bit of extra security to stop the dovetail sliding out. I’ve seen 12” Newtonians just held by a basic dovetail, it works but is a big ask.

At first I misread the title- “INSULTING A DOBSONIAN” It felt personal 😡😡 then I reread it and calmed down😊😊

Whatever binoculars are used they will gather much more light than unaided eyes. I fully agree with the idea of using binoculars with a smaller aperture than is traditionally recommended. Smaller binoculars are far less tiring to use, can often have a wider field of view. It’s a bit like telescopes- a smaller telescope is often much more convenient than a larger one and therefore is more likely to be used. It will show you more than a larger scope because its used more often. That’s definitely not putting down larger binoculars or scopes. When you do drag out the big guns the views are very rewarding. I can recall several sessions when viewing through a clubmates 20” Dob at Kelling Heath star party. An especial highlight was MI3. The view was fabulous, totally mesmerising, fondly recalled. But my 10” Dob from home “shows me more” because I can use it on any clear night. Ed.

When the door jammed on the EQ mount could it have been shifted away from polar alignment? It wouldn’t take much to cause tracking errors. You’ve said the mount was clicking. Is it possible that cogs have been moved out of line? Can they be adjusted? Hoping you sort it.

Hi Steve, from Chelmsford if you want to join a local club you have choices. There’s the North Essex Astronomy Club and Castle Point AC, near to Rayleigh actually Daws Heath. There’s others but these 2 are probably closest. CPAC meets weekly at St Michael’s church Daws Heath every Wednesday at 8.00pm or streamed live online. I would never promote my own club in any way except to say WE ARE THE BEST😁 Cheers from Ed.

Hi Steve from another Essex member👍 If you’re up for it there’s several astronomy clubs in Essex. Mine is Castle Point near Rayleigh. Always a warm welcome. Cheers, Ed.

Hmm….I’m thinking for that sort of damage to occur to the mirror still within the tube, then the external damage to the tube would be massive and very obvious. Agreed that this was a case of the designer biting off more than he could chew. Nice try, shame it didn’t work. Ed.

It should be possible to sort this one way or another. As the focuser mounting holes don’t match drill new ones but keeping the focuser lined up with the secondary mirror. Fit appropriate washers to the bolts on the inside. Or you could enlarge the existing holes in the appropriate direction. Instead of regular washers on the inside make shaped washers from thin sheet metal. Use matt black paint. A bit fiddly but quite doable to leave a secure and neat job. Edit- Make sure debris or tools don’t fall on the optics by keeping the tube horizontal. Or you could remove them completely while working. My own option would be to leave them in place, keep the tube horizontal on a bench and be careful. If the focuser base is a different radius to the tube make appropriate spacer(s). Again fiddly but doable, take your time, think it through, don’t rush you will get there😊 Ed.

Yes I saw that too👍 I was observing Jupiter and getting ready for the GRS rotating into view. Those 2 moons looked just like a double star. As the evening progressed their orbits caused them to pass each other as seen from earth. Quite fascinating as was the GRS later. SE Essex was “clear” last evening but with variable high cloud/haze. Ed.

Hi Mark. That’s obviously serious damage to the primary. So, was it originally supplied like that, or was it purchased then the new owner removed the mirror, dropped it causing the damage, then remounted the mirror, reassembled and sold it on? Either way that doesn’t speak well of someone….. Ed.

Years ago I got quite interested in the Cape Newise 8”. This was at Kelling star party in north Norfolk when the vendor had them on display. From what I can recall the concept was good but the execution difficult. Apparently collimation was very challenging. Occasionally they can be found on the second hand market, if the price was very low I might possibly take a punt….. Wow, talk about “thread drift”……guilty as charged😳

Indeed I have that book along with several similar by Richard Berry, Reg Spry, Charles Frank…. Fully agreed an optical window would be an extreme solution, but it has been done! Not an option with a basic workshop like mine but one for an optical expert with a relevant optical workshop and time to spare!

For us eyepiece junkies what a fascinating thread😊 Some rambling comments for what it’s worth… I don’t need eyeglasses to observe, but I use reading glasses for everyday use. My 3-6 Nagler has 10mm ER and I find zero problems in use…but if I do use reading glasses I can see the whole 50 degree field with the rubber eyecup folded. I own all focal lengths of TV Radians except the 3mm. As long as the click stop eyeguard is properly deployed I don’t have problems with eye positioning. I do accept others have problems. The original TV Nagler 4.8mm gets lots of complaints about tight eyerelief. When I owned one I found the eyerelief adequate for me without glasses. The problem I did have was constant fogging of the eye lens in damp conditions due to the close proximity of my eye. Apart from that it was an excellent compact high power eyepiece. My 35mm Panoptic is a lovely eyepiece. But reading various threads I discovered there were 2 versions. It would seem that both versions were optically the same. The difference was that early versions had the eyelens more deeply recessed than later versions. What year the change occurred I do not know. I have a set of original Vixen LVs. I like them a lot, especially the 30mm LV (this is not the later 30mm NLVW) In use I find the 30mm LV so wonderfully easy to use, my eye goes immediately to the right position. The 60 degree apparent field looks far larger than it is, in fact I prefer it in use to my 27mm Panoptic. And the 27 Pan is wonderful in other ways… I could ramble further, maybe later….

Hi Alan. Not sure what’s best. For deep sky fuzzies I don’t think it matters. But a top quality 6” is mainly a double star or planetary scope, that’s how I use mine. I’ve never used a curved vane spider although many have. I think the choice comes down to this:- The thick single arm secondary support you have holds collimation excellently, but gives a pronounced spike on very bright objects like Mars, Jupiter or Venus. A thin 4 vane spider holds collimation adequately. On bright planets a much less pronounced cross spike. A well designed and constructed curved vane- as said I’ve never used one, but people I trust like Gary Seronic says something like- 4 vanes concentrates the diffraction, curved vanes diffuse the diffraction across the whole field of view. Whichever you choose the diffraction is there, either concentrated into lines, or diffused across the field. An expensive option with no diffraction (other than from the secondary itself) is a full aperture optical grade window that holds the secondary in place. My only experience of that is my Edmunds Astroscan, but that’s definitely not a double star or planetary scope, but a low power wide field “sweeper” or comet catcher. You almost certainly won’t be taking that route, but when contemplating it is an option. Of course an optical window produces its own issues in addition to the cost, like how optically flat is it, how good are the coatings, where to I get one…..etc😊 DIY telescope making is a hobby within a hobby. But it’s a great hobby because the weather is totally irrelevant and you can spend many happy hours in your workshop, before binning it and starting again 😁 Yep, been there, done that! Again- corrections and comments welcome😊

I have used silicone sealant intended for construction or repair of glass aquariums to secure a Newtonian secondary. It may be that regular silicone would suffice, perhaps experts in that field would know. However given how disastrous it would be for the secondary to detach and fall on the primary, I’ve been prepared to pay the extra. Richard Berry, a well known telescope guru many years ago, used silicone to secure the primary, so it would seem a good plan. Commenting on your mention of stress released pyrex:- Again I’m not an expert on that, but wouldn’t it be possible to stress the glass by improper mounting? For instance, if edge clips as found on many commercially made scopes were clamped tight, even if the glass had been annealed and stress relieved, clamping down would surely stress the glass? If silicone was used to mount a primary, I don’t think a complete ring around the edge would be necessary. 3 blobs on the back surface should suffice. Advice from years back said support at 70% of mirror diameter from the centre, with thick nails under the mirror until the silicone had dried. This prevents the silicone from squashing flat. Once dried, remove nails. Comments and corrections welcome 😊

indeed 25585 is Richard, lives in the UK. I’ve bought items from him, he’s reliable, items accurately described and posted promptly.

In 1994 I purchased a 6” f6 Hinds primary and flat, and built it into a Dob. A recent rebuild included recoated mirrors at Galvoptics Basildon. To fix the primary to cell I used double sided foam tape. Please note I did not use double sided tape, but thicker foam tape. This secures the mirror without introducing stress to the glass. To further secure the mirror I used 3 brackets around the edge made from aluminium angle, with foam tape between bracket and mirror and between bracket and cell. Two things to note. I used top quality branded foam tape intended for outdoor use. The 3 brackets do not intrude onto the optical surface of the mirror. The views are excellent. The scope splits double stars beautifully. Saturn easily shows cloud bands, Cassini division, shadow of the globe on the rings…..quite stunning in good conditions. Similarly Jupiter is a fine sight, much belt detail, GRS, shadow transits like inky black bullet holes on the cloud tops…… Recently I took this scope to Alan’s house while he was contemplating his fine AstroSystems 6”. Mr Kipling made fine cakes, Mr Hinds made fine mirrors😊 Ed.

Hi Alan, just a thought….. You wish to make the primary cell collimatable. Presumably, as the original construction excellent it would only need a very minor tweak. I recall that the cell is fixed to the tube with 3 small screws into the edge of the cell. I know those screws are near the end of the tube, but is it possible to enlarge them a tiny bit? Then the cell could be moved a bit, hopefully to tweak the collimation into precise alignment by trial and error. Any movement could not be inwards because of the lip on the cell, but the enlarged holes could allow tiny movement of the cell away from the tube. I don’t know exactly how close those 3 holes are to the end of the tube, but you only need a smidge…. The above would allow you to fix mirror to cell as originally, then the focuser could stay as it is, plus the classic look would be retained. Ed.

Interesting comparison 👍……..as you say, a rarely used focal length. I occasionally use my Vixen LV 2.5mm on tight double stars in rare stable atmosphere. I love seeing the airy disc and diffraction rings, and of course it’s a delight when you finally split that double or triple after many tries!!