mikeDnight

Your TSA looks absolutely superb in its window setting. I think you could sell it to your better half by replacing the tripod with a solid wooden tripod that would go well with the wooden floor. Perhaps something like a walnut Gibraltar tripod. Then you really need to emphasize the classic, soon to be vintage nature of your incredible and valuable, rare as hens teeth world class refractor. I've always been lucky, as my wife has always understood my love of hobby and instruments, and since our first home together back in 1983, there have been scopes, tripods, books and globes around the house. She has never even hinted I relegate them to a shed, basement or observatory. She's even baked home made Apple pie for my astro buddies at 2am. And she paid for the materials so that I could build an observatory, as she didn't want me to get a chill due to winter breezes. 💖

Not a very good pic im afraid. Here's my Genesis 101 SDF ready to sweep some star fields. Still very pleasing views despite almost a full moon.

I had to check, but yes the Genesis SDF is definitely F5.4. I think the original Genesis was F5. The SDF was the second incarnation of the Televue 4", which I believe was released in 1993. Im uncertain as to whether the original Genesis F5 used fluorite, but perhaps the slight increase in Fratio helps with colour correction?

What did I see tonight? Street lights across town through double glazing. I know it sounds silly, but it was cloudy and I wanted to try out various eyepieces in my vintage F5.4 Genesis SDF just to see if everything reached focus. I only currently have one Nagler eyepiece, a 31mm which gives 4.8° true field. All my Morpheus come to focus as do my collection of pseudo Masuyama super plossl's. A mini wow moment was when I used my 3.4mm Vixen HR, which is narrow field but stunningly sharp even in the SDF. Surprisingly the masuyama's are excellent in the SDF too though they aren't wide field. I have to say the Morpheus are quite a revelation even at F5.4, with the 17.5 and 12.5mm giving superb views. I just need a few clear nights without a moon on view to get the most out of this scope. I must have particularly good glass in my double glazing as the diffraction pattern both inside and outside focus was excellent, while in focus even with the 3.4mm HR it remained wonderfully sharp.

I think Vixen still offer some pretty top end Japanese ED's as their high end scopes, but I do think that Takahashi set the standard that others try to emulate. Some more successfully than others.

Don't get me started on TV undercuts. I hate them! What Al probably means is that TV profits won't be as high as he'd like them to be on a visual refractor, though I do think there would be a significant following who would buy Televue if they were available. They like to charge high prices for everything, though you may not have noticed. Just going back to the NP101IS, by reading user experiences on CN, there appears to be a consensus that as the power increases the image softens. Perhaps it's because warm air trapped between the widely spaced front and rear doublets can't escape, or may be the lenses are just not up to the job. My NP101IS suffered from that problem and so does my vintage SDF, but on wide fields they are glorious.

I do like the clean look of Televue scopes, and may be if I'd bought a TV 102 instead of a NP101IS, I'd still be using it. From memory though, the 102 wasn't cheap, especially for an ED, and I felt there were other beautiful doublets on the second-hand market for less that could possibly run it ragged. I think today if I wanted an RFT visual quad that could perform on the Moon and planets, and could afford it, I might possibly go for a FSQ106. Then again I'd most likely forfeit the 5° field and go for an off the shelf Starfield 102, Vixen 103 ED, or Tak FC and save a small fortune.

If my eyepieces fog over, I usually just fan air over them with my hand. They usually clear within a few seconds. Personally i wouldn't use a cloth of any kind to wipe away dew, as there's a chance of damaging the coatings over time, also moisture may remain around the edge of the lens. Worst case scenario I would warm the eyepiece in my hand or car, or by taking it into the house for a few minutes. A hair dryer can speed up the process but without high heat.

I've seen it in my FC100DC and found it easy, but I suspect much depends on the illumination and seeing conditions. I should add that I almost always use a binoviewer for observing the Moon, and that makes seeing fine linear features less challenging.

I quite like the technique you've used Mike. I suppose hetching is harder to use to represent fine detail than the stippling technique used by the likes of Harold Hill and Nigel Longshaw. The problem with stippling is that it can be a laborious task, but beautiful when completed. I've tried it but find general shading techniques easier. Hetching could be something I might try as it seems a more relaxed drawing style.

Thats an excellent sketch Mike. I find the Moon to be the hardest of all astronomical targets to sketch, so thanks for fanning the flame. I need to sharpen my pencils as the night's get milder and the Moon gets higher over the spring months.

I think the difference is that the 10" has just over 28 square inches more surface area than the 8", and so will give you better resolution and greater light gathering power. So a 10" has the potential to show you finer lunar and planetary detail, and will show fainter objects such as galaxies brighter than they would be in an 8".

Wow! Thanks for that blast from the past. I remember it well. How advertisements have changed!

It's sad to see it go that way. It's also sad that your son is embarrassed by having a tardis in the garden. I think a giant mushroom would be more garden friendly, where the mushroom would in reality be a rotating dome. Surely he couldn't find fault with that!?

I bought a TV NP101 IS about 13 or 14 years ago. Televue claimed that "It Is What You Want It To Be!" Unfortunately it wasn't what I wanted it to be, which was a lunar and planetary scope in an easy to handle package. I know many would argue the NP101IS gives great views of the Moon and planets, but they are just ok from my perspective. It was an expensive scope that couldn't deliver the same crispness of planetary image delivered by a much cheaper Vixen ED, so I sold it. It was however a stunning visual RFT, the best I've ever used. I think its lack of planetary punch is in part down to its short F ratio, plus four elements combined with the multi element Nagler eyepieces and powermate needed to reach an acceptable magnification. All the above takes the edge off the definition that's so vital for planets. Having said all that, the sketch of Mars in my avatar was drawn through my NP101 IS. I did like the 101 for its visual rich field capabilities, in fact I loved it, but I needed a top class planetary scope, so in that sense I feel Televue grossly exaggerated their claims regarding the scope. Their philosophy really is the "Space Walk" experience, and in that regard their scopes really stand out and shine. I recently bought a vintage Genesis SDF for a fraction of the price of a new NP101IS. Although it isn't truly Apochromatic, it is everything I loved about the NP101 IS, its star images are textbook perfect with no hint of spherical abberation, and better than the IS I owned. So buying an older TV scope second-hand may be the better option. I know the optics for the earlier TV refractors were made in Japan but I'm not certain that is still the case. Perhaps others may enlighten me?

FLO sell a 2" 35mm Tak extension tube. If you remove the 1.25" eyepiece holder and fit a low profile 2" to 1.25" reducer into a 35mm extension, you may get what you need. Take a look at the Tak accessories or ask FLO for advice.

I wonder if prism vs mirror played a part in perceived brightness?

If that's true Dave, then why are you talking to us?

Thanks Stu. I saw the ad and didn't respond until the next day, as normally after a short while thinking about a purchase I think better of it. But it was the first thing on my mind when I woke the day after, and as it was a seller near to me I could drive over and collect. I did like my NP101 that I had for only a year some 14 years ago, but only for its wide field ability. It was ok in other respects but that's all, and it wasn't worth the extreme high price I paid, even less worth today's astronomical price. The Genesis SDF however was well worth the price asked. I think the SDF and the DZ will get along nicely, as there's no need for any competition between them. I'm still stunned by the view of Sirius! I'm not certain how old the GSDF is but I think it may be from the 90's. May be someone could enlighten me?

Here's the latest edition to the arsenal, a Genesis SDF F5.4. As it happened the sky was clear as the Sun set and as the stars started to show, I played around arming my way around this scope, and what it can and can't do. The night was cold and misty, which meant steady seeing but with plenty of moisture condensing on the tube, in fact water was pouring down the tube. The objective remained unaffected. After an hour or so I decided to bring the tube back into the house to dry it off and let it warm up, ready for a second session later. The first thing that jumped out at me was the CA. Despite being a fluorite quad, this is no Apochromat. Much of that first impression of the CA was amplified by the mist. However i wasnt too bothered, as the magic of this scope is its wide, rich starfields. Nearer midnight i took the SDF out for its second session. This time the Moon had moved away and didn't dominate the sky anymore. Sweeping through Auriga and Orion with the 31mm Nagler was a joy to behold. With the 17.5mm Morpheus in the diagonal, I swung the scope over to view Sirius. I thought there's no point in messing around, let's try and kill it on its first night out with me. To my surprise, the CA I saw earlier was nolonger nearly as evident, and Sirius stood almost motionless due to the steady seeing. There was no evidence of spherical abberation and diffraction rings were virtually identical on both sides of focus. I was very pleased. What thrilled me most of all however, was that the Pup was kissing the first diffraction ring. I don't remember ever seeing Sirius as steady as it was last night. As a wide field sweeping instrument the Genesis SDF is superb, and fills the gap left by the sale of my NP101IS from 14 years ago.

Believe it or not, Venus is a good planet to cut your sketching teeth on as at first it looks bland and devoid of detail, but it isn't, its loaded, and it really demands you pay attention to very subtle albedo features. Once you notice the detail its hard to understand why others can't.

You should be proud of your sketches Nicola, the really are excellent. I really like your M13 and M45 as they both gave me a mini wow moment as I scrolled down your post. Very realistic! 🏆 They say if you really want to see an object, try drawing it. I'm sure you'll find that to be true as you thrill yourself, and us, with more of your observational sketches.

At the end of every observing session i always check the lens hasn't dewed over before bringing it back in the house. If the lens is clear of dew, I blow over the lens with a bulb blower just to remove any dust or pollen, then I cap the lens and bring the scope into the house. If the tube is wet I'll dry it off, leaving it on a mount or on he dining table. If the lens is dewed over, I don't clean it off, but bring the scope back into the house uncapped leaving it uncapped over night so the moisture evaporates. As for cleaning a lens, I think I cleaned my FC100DC twice in five years, and haven't yet cleaned my FC100DZ at all in the almost 20 months I've had it.

I think I'd be inclined to dig out an approximate cubic yard of soil beneath your decking. Insert a steel pier and pack the hole with rubble and concrete. I may even fill the steel pier with rubble and concrete, or sand and cement just to add a bit more solidity. That's what I did with my home made 6" square steel pier, and its as solid as I could wish for. It could carry anything! I left a 1/2" gap between the wooden floor of my observatory and the pier itself, just so vibration from walking around didnt impact the telescope. If you did move house in the future, just stick a bird table on top of it and the new residents will love it; that is until they try moving it.

I sometimes use a red torch with adjustable brightness, but even then, shining it directly at the paper its too bright. So I aim it away from the paper and often cover the light with my hand to shield my eyes from the light source. It can be a struggle to sketch in the dark, so I use a rough sketch book for sketching at the telescope, then afterwards, I make a cleaned up version of the sketch in a higher quality sketch book. I have a kind of method of noting brightness intensities of planetary detail using a combination of numbers from 0 to 10, with z representing 0 to prevent confusion with small circular details. Also, I use various kinds of hetching for darks. For nebulous objects I usually draw in negative, with the brightest areas being the darkest, then convert the sketch into negative using photo editor to give a realistic impression. (A putty eraser is an invaluable tool for lifting graphite off the page to create lighter areas). Below is the torch and the angle poised lamp in my observatory that can be aimed to suit.