johnturley

I think its actually about 35 mm outward travel with a digital SLR (I must check with mine), were you meaning with an eyepiece. John

Finally picked up my Esprit 150 from Es Reid in Cambridge on 21 September after a 7 week wait, Es tested both the scope and the field flattener last week and found them to be excellent. Interestingly Es also checked over a second hand Tak FS152 the same week, and was able to compare the two scopes, in his opinion there was no discernible difference between them. John

Ordered one from them to fit my Esprit 150 last Friday having read 2 favourable reviews, it arrived today (Wed 9 October), and would agree that they appear to be well made and of good quality, superior to the Kendrick ones of which a have a couple. I wouldn't however give them 10 out of 10 on customer service, I initially asked by email what size I should purchase to fit my Esprit 150, which has a dewshield 8in or 203 mm in diameter, but didn't receive any reply after several days. In the end I decided to order the 8in model, but found that it is a bit on the big side, and could have probably saved myself a bit of money by going for the 6 or 7in version, however I'm not bothering to send it back to exchange for a smaller size. John

I finally managed to get the Esprit mounted up and operational Wednesday of this week. It took longer than expected as unfortunately, due to a misunderstanding, the local engineering firm made the forward support bracket 6 mm shorter than it should have been, so that although I could mount up the Esprit ok, it wasn’t possible to align it with the 14in Newtonian so that the same object appears in the centre of the field of view through both instruments at the same time. As can be seen in the photos the rear support bracket has a small amount of sideways and up/down movement to enable alignment of two scopes. I was a bit nervous about how easily I could balance the scope on my 14in Newtonian, but despite the 12 kg weight of the OTA (around 15kg including tube rings, finder and star diagonal), I managed to balance it up ok (see photo), and with the slow motions working fine. In fact it made wonder how large and heavy a scope I could actually mount on my 14in Newtonian which is on a massive fork mount, maybe the absolute maximum would be a 180 mm f7 refractor such as the CFF and TEC which both weigh around 18 kg, but cost around £16k and £21k respectively, so don’t think I’ll be going that way anytime soon if ever at all. I’ve actually installed my ES 8x50 erect image straight through finder (see photo), rather than the Skywatcher 9 x 50 right angle finder that came with the scope, as the former appears to be of better quality, and has an illuminated reticule, although I know some prefer right angle finders. I’ve also utilised a Baader click-lock diagonal rather than the included Skywatcher one for the same reason, and although there was sufficient travel on the focussing mount to reach focus without the need for extension tubes, I preferred to utilise a 50 mm Baader click lock one, so as to avoid racking out the focuser towards the end of its distance of travel. It also makes it easier to remove the diagonal and fit an additional extension tube for straight through viewing. Although some have posted stating that they did not like the capstan wheel type arrangement for rotating the focuser, I actually quite liked it, and think that it provides a much more rigid arrangement for locking the focuser in a particular position than that on the ES scope. The focusing mount tension screw on recent models has been replaced by a spring loaded locking leaver, and whilst this may please AP enthusiasts, I think that I would have preferred the former. The lens cap which unlike that on my ES Refractor, fits over the dewshield rather than the lens cell, being made out of fairly thick gauge metal is quite heavy, I’m surprised they don’t use a thinner gauge metal or plastic, but it does roughly balance out the weight of the main mirror cover. I can see the pros and cons of either, fitting over the lens cell is probably better for keeping out dust and moisture, but depending on the rigidity of the lens cell, maybe continuously removing and replacing over a long period could possibly effect collimation. I also needed to fit a handle to the one on my ES Refractor to remove or replace it as, because of the way the scope was mounted, I could not fully retract the dewshield to do so. I also find it useful that, unlike on the ES Refractor, the dewshield (which is quite a sloppy fit) on the Esprit can be locked in position via 2 knurled knobs. I ordered the matching field flattener with the scope, but found that it is a bit fiddly to fit, as you need to unscrew the 3in to 2in reducer on the scope, fit an adaptor, then the flattener, then fit the matched extender tube, and then the 48mm to Canon (Nikon or Sony) adaptor, not ideal in the dark, hence I wonder how often I will actually use it in practice. The ES field flattener (which is actually an Ascension branded product from Opticstar designed for triplet APO's in general), came with a ‘T ’thread to Canon adaptor which fitted directly into a 2 in drawtube, and although obviously not a good as the Esprit matched flattener, it might still give quite good results with the Esprit, at least better than using no flattener at all. The larger size in the case of the Esprit matched flattener is because it has a clear aperture of around 60 mm, which I assume is necessary to provide the 44 mm image circle. I looked at a few objects Wednesday (one of the very few clear nights recently) including Saturn, viewing conditions were not ideal, but as expected the Esprit gave much sharper star images than the Newtonian, and under the prevailing conditions also on Saturn, plus as free from any false colour. I could just make out Cassini’s division through the Esprit, but not through the Newtonian (although it does show up clearly through it under good conditions), obviously the Newtonian gave a brighter image, and more moons were visible. The image through the Esprit 150 was though as expected, noticeably brighter than through the ES 127, and Titan showed up clearer. I find it useful having a refractor piggybacked on the Newtonian, as depending on what you are looking at and the viewing conditions, one instrument or the other will give the better view. John

I have bought a number of items from Rother Valley Optics, who are my local supplier being situated just 15 miles (30 mins drive) away, these include two telescopes, a number of eyepieces, filters, and several other items, coming to around £5,000 in total. I have always selected the option to 'collect goods from shop' as this saves on shipping charges, plus I can inspect the goods before taking them away. I have generally found them to be very helpful and have offered good advice, but I was a bit disappointed with them when it came to obtaining a Seymour Solar Filter to fit my Skywatcher Esprit Refractor. According to their website they stock Seymour Solar Filters in a large number of sizes, but not apparently the correct one to fit my Esprit 150 (which appears to be the SF 8376). However when I asked them about obtaining one for me, they were not willing to do a special order, and informed me that I would need to order it myself direct from Seymour in the USA which will involve additional shipping charges, plus probably also import duty and customs clearance charges. Bearing in mind the amount I have spent with over the years, I really thought that they could have been more helpful. John

Finally picked up my Esprit 150 from Es Reid in Cambridge yesterday after a 7 week wait, Es tested both the scope and the field flattener last week and found them to be excellent. Interestingly Es also checked over a second hand Tak 150 the same week, and was able to compare the two scopes, in his opinion there was no discernible difference between them. However when it came to price there would have been more than a discernible difference, the new Esprit 150 (which comes with tube clamps, 9x50 finder, 2in star diagonal, and 28 mm eyepiece) plus field flattener cost me around £4,300 (from FLO), whereas a new Tak TOA 150B (from RVO) with tube clamps and finder, plus field flattener would have cost around £14,500, similar also to the cost of a TEC 160 (and approx. 6 month wait). The scope was very well packed in a substantial case, which in turn was packed into a cardboard box with extra packaging, I gather from Es that it is very rare one suffers from transit damage. The whole scope appeared to be well finished and engineered, substantially better than my Explore Scientific 127 APO, and also an 1987 vintage Astro Physics Refractor that I used to own. In particular the focussing mount was very smooth, and provided 85 mm of travel, as opposed to the totally inadequate 45 mm on the ES Refractor, and think the majority of users won't find the need to upgrade to a Feathertouch focuser, which appears to be no longer offered as a factory fitted option. Surprisingly the tube length was shorter than I was expecting at around 75cm with the dewshield fully retracted, and only some 2-3 cm longer than the ES Refractor despite the extra 9.5 cm of focal length, most of this it appears is taken up in the focussing mechanism. The tube diameter was also greater than I was expecting at around 180 mm (with some scopes the tube diameter is only around 5 mm greater than that of the objective), the larger tube diameter should help to reduce tube currents. Although it is quite a heavy scope for its size, as I was half expecting I measured the weight of the OTA (without tube clamps, diagonal, finder, etc.) to be lighter than stated in the literature at 12 kg rather than 14.5 kg , similar to that of my AP Refractor (which I also mounted piggyback), and is not too difficult for one person to lift. My only criticism (so far at least) was that the layer of felt liner on the tube clamps was very thin (compared to that on the tube clamps of the ES Refractor), and can understand why some people may have had problems with the clamps gripping the scope sufficiently, I do however have some self adhesive felt which I can add on if necessary. I haven't however has the chance to try it out yet, as apart from the weather, I need a local engineering firm to machine some modifications to the tube clamps before I can mount it piggyback onto my 14 in Newtonian, and have spent part of today making a wooden template for a new support bracket for them to machine in aluminium. Will post further after I make my first observations. John

I've never been able to see Triton visually even through my 14 in Newtonian. John

If you are using a full frame digital SLR the 48mm is better, as you can get slight vignetting with the 42mm T thread, with a crop frame sensor it probably doesn't make much difference. John

Mart Hope you mount arrives ok this week, do let me know how you get on with it, send me a PM if its easier. Having read Johninderby's comments, I am now increasingly thinking of getting the AZ-EQ5, like you from my local supplier Rother Valley Optics, especially as it is already belt driven. Ideally I would liked to have a look at both versions before making my mind up, but as I expect you are aware, they don't have either version in stock or on display, did you have to wait long for yours. Cheers John

That's good, if you add on the cost of the belt modification this reduces the price gap between the two mounts to less than £100. John

Hi again John Thanks for your reply, it sounds like for what I want the AZ-EQ5 would be the better choice, I take it that you didn't bother with the Rowen Belt modification, I'm not sure whether its available with the AZ-EQ5 anyway. John

Hi John Thanks for your reply I take it that for quick grab and go then you recommend the AZ-EQ5 in preference to the HEQ5, I assume that there is no significant weight difference between the two versions. John

I would actually be doing mainly visual with the ES 127 on the new mount, I wanted it as a quick grab and go scope which I can move around the garden, and occasionally transport to different sites, when the view from my observatory shed is obscured by trees on neighbouring properties, which unfortunately have grown so much in recent years. I would though want to use the scope in driven mode to track the moon and planets, I didn't know whether the AZ-EQ5 can track objects in altazimuth mode same as the Celestron CPC does. Many years ago I used to have a 10 in Newtonian on a Fullerscopes Mk3 equatorial mount, provided that the polar axis was set at the correct angle, and was pointed roughly in the direction of Polaris, then this was sufficient to keep an object in the field of view for several minutes at medium magnifications. The mount had a manual slow motion in declination but not in right ascension. John

It would be interesting to see some recent comparisons with high end scopes such as TEC, TAK and CFF costing several times as much. There was a comparison on Cloudy Nights a few years ago between an Esprit 150 and an AP 160, the AP scope came out as only being marginally better despite the huge price difference. John

Are some other retailers being less than perfectly honest regarding certain items currently being out of stock. For example, according to a couple of other retailers' websites, the Esprit 150 is currently 'In Stock', however I have my doubts as to whether this is actually the case as I was under the impressions that all Skywatcher products in the UK are sourced via the main importer (Optical Vision in Bury St Edmunds I understand), and stated stock levels refer to what is in stock with them rather than the individual retailer. Even if other retailers do have the Esprit 150 in stock, I preferred to wait to get mine through FLO, as I particularly wanted the Es Reid Optical Bench Test, which I understand is exclusive to FLO. I gather that problems due to misalignment of the lens elements (frequently as a result of rough handling by couriers) is not uncommon, not only with Skywatcher Refractors, in particular the 150 ED doublets, but also with some Williams Optics, APM, and CFF Refractors. John

You can't beat old fashioned setting circles and a sidereal clock, I found it straight away using this method. John

I also observed the conjunction from Dronfield, conditions were a bit variable with clouds coming and going, I was a bit lazy though and didn't bother to set up my camera to take a photo. Interesting too that you also appear to have imaged Triton, I also caught it when I photographed the close conjunction of Neptune and Mars last year, I've also never been able to spot Triton visually through my 14in Newtonian, it may become easier in future years as Neptune gradually moves higher up in the sky. John

Originally Pluto was tracked down by Clyde Tombaugh based on calculations by Percival Lowell, which were based upon perturbations in the orbit of the planet Uranus, and to have these measured effects, the mass of Pluto was calculated to be similar to that of the earth. Now we know that the mass of Pluto is less than one hundredth of that of the earth, it could not possibly have had these gravitational effects on Uranus, and its discovery is now put down to a lucky coincidence. John

I am also planning to get a portable mount on which my to mount my ES 127 Refractor (currently mounted piggyback on my 14in Newtonian) after my long awaited Esprit 150 arrives, and was also thinking about the Skywatcher HEQ5 (possibly with the Rowan Belt modification) from RVO (also my local supplier), but had also thought of the AZ-EQ5. However I don't think that in practice I am likely to make much (if any) use of the altazimuth facility, and get the impression that there are more likely to be problems with the AZ-EQ5, and that it is more awkward to set up. John

How many objects would you classify as being planets if Pluto was classified as a planet again. You would have to include Eris (whose discovery was partly responsible for Pluto's declassification) and possibly also Makemake and Haumea, and with new discoveries the list would continue to grow. You have to remember that when Pluto was first discovered it was thought to be around the same size as the earth, this later got revised downwards to around 3,600 miles in diameter (still larger than Mercury) and more recently to around 2,000 miles (smaller than our moon). John

Interesting that the design of your fork mount appears similar to that of my 14in Newtonian built by Rob Miller of Astro Systems in 1984. John

The original 13 mm Nagler was certainly large. John

The waiting times for Esprit Refractors is considerably less than those for premium brand APO Refractors such as TEC and CFF, most of which are made to order and involve a wait of at least 6 months. Furthermore from what I gather, the performance of Esprit scopes comes very close to if not quite equalling that of premium brands costing several times as much. John

Yes, for some reason they cost about 20% more in the USA, never fully understood this as Explore Scientific scopes work out about the same. John

Which country were you in at the time John