NGC 1502

The 3mm ( at least ) thickness for the silicon is important to allow the probable difference in expansion and contraction for the glass and cell. If you get it wrong, then the mirror can be stressed, easy to see with a triangular shape to a defocused star. The “triangle” can be quite subtle and easily not noticeable...... And yet, back a few decades Astro-systems of Luton glued the mirror to the aluminium using a circular piece of what looked like green snooker table cloth, to make a “sandwich” of mirror/glue/cloth/glue/aluminium - this was over the whole of the back surface of the mirror, it worked very well indeed. That’s probably because the glue didn’t penetrate the thick cloth and so allowed the glass and aluminium to expand and contract independently. At least that’s how I understand it. Peter Drew on here could comment I’m sure, because he was one of the top people at Astro-systems. Apologies if my understanding is off the mark...... And Neil, if I were you, I wouldn’t fix your mirror to the ceiling ? Ed.

I’d probably feel a bit naffed off myself if a freshly coated mirror didn’t look perfect. But your earlier post mentioned that you got good views from the mirror before the recoat, so I think the coaters would be right in saying the less than perfect coating will be ok. Hope you feel a lot better when you get first light from the refurbished mirror. Have a look at some of the more famous objects to cheer yourself up ? HTH, Ed.

No problem Louis, as I mentioned, others may find differently to myself. I think eyepiece choice is a personal one, what suits one person may not suit another. I do find however that eyepiece usage is quite different by day than at night. During the day, with a dilated pupil, I find my short eye relief eyepieces very uncomfortable to use, but at night they are fine. I have a type 1 Nagler 4.8mm, with a listed 7mm eye relief. By day I find it almost unusable, but at night it’s ok. Longer ER would be better of course. However, with my eye so close to the glass it mists up more easily. No doubt the Pentax XL range were excellent and highly regarded. I used to have just one, the 10.5mm and I found the 65 degree field noticeably better than the 60 degree Radians. If they had been easily available when I bought the Radians I may have built up a set. Ed.

I would agree. On Cloudy Nights I saw lots of posts about the “coffee tone” colour ( sorry color ? ) they were supposed to have, but comparing with other makes I could never detect that. Poor old “uncle Al” great guy who’s products sometimes come in for unwarranted criticism. Ed.

Just a comment on the Radians, and very definitely not to argue, just for balance for anyone considering used Radians. I’m a Radian fan. If the eyecup is set too low, that means your eye is inside the 20mm eye relief, and kidney beaning is certain, same as any other long eye relief eyepieces. So setting the adjustable eye guard to suit you is crucial. Get that right and I find they are excellent. Others may possibly find different. And if you find the eye guard action too slack or too tight, it’s a DIY fix. Ed.

That’s my thoughts too. With my 10” Dob, 150 -200x are good, but only if the seeing is steady enough. I keep a 9mm Ortho handy for 133x and find that better at times. A smaller and sharper view beats larger but fuzzier, good planetary views are much more dependent on steady seeing than eyepiece choice. +1 for Orthos. I find the eye relief ok down to a 6mm, although I don’t wear glasses. Ed.

My local branch of Snappy Snaps ( Southend on Sea ) recently gave me a free bag of 35mm film containers. As they process film and sell it too, they accumulate empty containers and just put them out to recycle. Ed.

It’s possible to aluminise, but you probably know the kit is very expensive, and specialised. An astronomy venue I used to visit ( Fieldview astronomy B&B ) had the kit, but they had issues with uneven coatings, and the pump took hours to produce the required vacuum in the coating chamber. Not sure, but I think they gave up on the idea. They also changed the business to cater for the birding community when the starcamp moved from Thetford to Kelling Heath and greatly reduced the numbers of astronomy visitors. Ed.

Hi Niel, one of the great things about basic Dobs is the way simple DIY fixes work so well. About the only thing we can’t do is re-aluminise the mirrors. I’m really fortunate to have Galvoptics just 10 miles away, a family firm I’ve used several times with no problems. You could use furniture sliders as a temporary substitute for Teflon, would get you up and running. Yet another simple low tech fix........? Ed.

Great scopes from a sadly different era, although many of us prize kit like that ? Indeed the mirror needs a recoat, but you may be surprised at how well it would work as it is. Best wishes with your “new” scope, Ed.

Most built in dew shields are too short, but can easily be made longer using above methods. If that’s not adequate, and it probably won’t be on chilly nights, there’s heating bands that gently keep the objective just a fraction above ambient, or a 12v hairdryer from a battery pack. Ed.

I’ve made several dew shields for small telescopes from regular camping mat foam. It’s widely available from ‘outdoor’ type shops, is lightweight, doesn’t absorb moisture ( just gets wet ) and is easy to cut. No reason why it won’t be fine for binoculars. I once found the foam in black which is ideal, but any dark colour would be ok. HTH Ed.

Lots of good advice already given. I’d like to add : Best not to check mirrors by shining a light down the tube at night, most look horrid like that. Check in normal daylight. If you decide to clean, leave it for a few days, then think - is this really necessary? If you go ahead, get everything you need ready, choose a time when you won’t be disturbed, don’t rush, don’t fuss over every tiny spot or streak. Don’t start late in the afternoon when it looks like it’s going to be clear........ HTH, Ed.

Well Dave, shame your in Dorset, but at least we can chat on here, with no petrol costs ? Noticed in your signature you have some circle T Orthos, I have some of them too. Looks like we’ve both got it bad ? I’ll check back tomorrow, Ed.

Hi Dave. What made me ask the question of a collimatable cell, is because the pic in your first post showed a black objective cell that’s flared out to larger than the tube, same as mine, to accommodate the 3 pairs of screws. I’m no Vixen expert, but I’ve noticed that later versions had a slimmer cell that was not collimatable. I’m guessing that Vixen decided that as their build quality was very good, and slow focal ratios are not at all critical for collimation, non-collimatable cells were fine. I’m fond of classic stuff, my elderly Claud Butler bicycle, early Asahi Pentax cameras and Takumar lenses, a collection of Weston exposure meters, just ooze nostalgia for me. Cheers from Ed.

Hi Dave1, that’s a very nice scope, great for planets and double stars. The correction will be excellent. Pics below of my shorter F11.4 version. As you can see, mine has the original focuser, and a collimatable cell. Agree that yours will be an 80s scope. Looking at your lens cell, is it collimatable ? Of course, at F15 it will be very tolerant indeed of any slight deviation from spot on. Later versions of mine came with a non-collimatable cell, probably because Vixen decided that would be fine. Thanks for sharing a lovely classic, Ed.

Just had excellent service from ENS. Item sent promptly, great condition as described. Not the cheapest, but if it’s a reliable source that accurately describes what is for sale, that in itself is worth a bit extra money. And of courage you can phone first to ask questions about an item, which is what I did, and got friendly helpful advice, with no hard sell. Would buy from them again. Ed.

Lots of good advice already given. But I’d like to add that the chairman of my local club who has decades of observing experience has a Heritage 130p and reckons it’s great. Says it all I think ? Ed.

Hi Dave, well done for getting things sorted, and good that you’re delighted. Hoping your next observing opportunity goes well, I’ll check back and see what you say. But if you’re not careful, you may be asked to do a “me and my scope” talk at the club Ed.

+1 for it needing an obsy, unless you are a very strong chap Apart from that, a classic scope, well worth sorting. Regards, Ed.

Nice EPs Shane I can never quite make my mind up as to what I like best when it comes to eyepieces...... I thought I had my ideal set, a 27 Pan, a couple of Radians, and the 3-6 zoom to cover all my needs....... That's until last year when a local clubmate was selling a 24 Pan and a 9T6 Nag for such a great price I couldn't resist. I just love the comfortable eye relief of the 27 Pan and the Radians, plus the sharpness and flexibility of the 3-6, but the small & light 24 Pan, and lovely wide field Nag is very addictive..... Also, the lightweight 24 Pan, 9T6 & 3-6 are all I really need, one in the focuser, other two in my pockets, they all take the same dustcaps, are precisely parfocal and I can leave the 2" to 1.25" adapter in the focuser for the whole session..... I've looked through other peoples Ethos's too, wow ! But not going that route........well not just yet Regards, Ed.

Hi Janie. Light pollution doen't help of course, but there's loads to see, even from a large town. If you can find a place that has no direct light from neighbours or streetlights, that helps a lot. I use a tarpaulin pegged to my wife's greenhouse to shield nearby lights. Lots of options to shield nuisance lights according to your individual circumstances. The moon, planets and double stars are the least affected by light pollution, lots of the brighter deep sky objects available too. Another option is to get along to a local astronomy club, most are happy to help. Maybe let us know how you get on ? Regards, Ed.

If you have a standard Newtonian reflector, the secondary mirror is much more prone to dewing than the primary that's deep down at the lower end of the tube. You may be able to reduce secondary dewing by extending the upper end of the tube with a 'camping mat' dew shield, or perhaps by pointing a 12v hair dryer down the focuser after removing the eyepiece. But the best solution is a proper dew heater like the ones in this link http://www.kendrickastro.com/newtonian.html#Secondary (scroll down). The heat is very gentle, to keep the secondary just above ambient temp. There are DIY versions if you are handy. HTH, Ed.

That's very helpful for your first post, welcome to SGL sounds like you will be an asset here. Regards, Ed.

Hi to you in AZ. It's great when you get a proper thought out response. Makes you feel you got a product from a manufacturer that wants to help, rather than "we have your money, good bye" You live in a great part of the US, Baringer crater, Lowell, AZ dark sky village, Grand Canyon, so much more.....it would be the holiday of a lifetime, if ever I get around to it........ Enjoy the new scope, Ed.