johnturley

It's the same as in the UK, my wife has lived in the in the UK for nearly 25 years, however she isn't allowed to vote in General Elections (only Local Elections) and wasn't in the EU Referendum. John

If you replace the 1.25 in nosepiece on the filter wheel with a 2 in nosepiece, you might find that you have just sufficient 'In Travel' I fitted a 2 in nosepiece to my ZWO filter wheels, which gave my about an extra 10 mm of in travel, which was sufficient in my case, it all depends on the scope. In addition it is possible to move the focusing mount slightly towards the main mirror which will give you extra effective in travel, but this will involve drilling new holes in the telescope tube, which I understand not everyone would want to do. John

Maybe an ES 2in 2x Barlow would fit in nicely John

I've just accessed the site, and it seems to be working fine. John

An easier method if your mount has setting circles and a meridian pointer (which I use with my 14 in fork mounted Newtonian) is via a sidereal clock, although you don't need an actual clock these days as sidereal time for your longitude is available as an app on iPhones. You simply set the meridian pointer to local sidereal time on the RA Circle, and then move the scope to the RA and Dec of the desired object, assuming of course your mount is reasonably well polar aligned. I find this particularly useful for locating Mercury and Venus in daylight, when you can't star hop. The problem is that most scopes that actually have setting circles these days, is that the circles tend to be too small, ideally you need an RA circle at least 12in in diameter, my fork mount has a 12in RA circle with each hour subdivided into 20 minute and 4 minute segments. John

Ed said that he liked eyepieces with a dual 2in/1.25in barrel which used to be quite common. Personally I disliked them as it made the eyepieces more bulky and heavier than they otherwise needed to be, and I was always dropping the removable screw and then having to search for it in the dark. I agree with him however that it was a shame that Tele Vue discontinued their 26 mm Nagler eyepiece, I was until recently on the look out for a good secondhand one, but opted instead for a Stella Lyra 30 mm UFF, which cost new less than half of what I would probably have to have paid for a secondhand 26 mm Nagler. John

I always say that the ideal punishment for those opposed to adopting the Metric system, would be to lock them in a room, and then make then do Physics and Engineering calculations using old Imperial units. I still however remember the diameters of the planets, and their distances from the sun in miles. John

Amazing that you could make out the North Polar Cap on Mars with the tiny disc now less than 6 arc seconds. John

Unfortunately I do not think that the stock focusers on the Esprits are up to coping with heavy accessories such as a digital SLR, on the other hand I do not find much of a problem with my ZWO ASI 462 camera mounted on my Esprit 150 with the stock focuser. John

Observed Venus while it was still quite high up in the early evening yesterday, and which was displaying a nice gibbous disc. Whereas Venus at magnitude -4 was quite easy to find in daylight with my old fashioned setting circles and sidereal clock, I was unsuccessful in trying to spot Mercury at magnitude +1.4. I put the failure down to insufficient contrast with the bright early evening sky before Mercury went down behind a neighbouring house. I find Mercury fairly easy to pick up in daylight when it is brighter than zero magnitude, it becomes progressively more difficult between zero and +1, and very difficult to find when fainter than +1, although I have managed it on previous occasions depending on sky transparency. John

It actually states 50 degrees on the barrel.

I have both the 3-6 mm Nagler Zoom, and a 4mm Vixen SLV, I find the results with the Nagler Zoom on the moon and planets to be at least as good as the 4 mm SLV, and has a significantly wider field of view. Although it states 50 degree APFOV on the Vixen SLV, I find it to be nearer to 45 degrees. John

I can recommend the Stellalyra 30mm UFF, it works quite well in my f5 Newtonian, although the edge is not perfect, it is vastly superior to my 36mm Baader Hyperion Aspheric. John

I tried silvering a mirror (Brashear's process I think) while I was at school in the late 1960's, it wasn't very successful, the coating was very thin, and rubbed off when I tried to clean it. Even if successful silver coatings used to tarnish quite badly after only 6 months, at that time aluminium coatings used to last about 3-5 years. Nowadays modern enhanced aluminium coatings, such as Hilux offered by Orion Optics UK if looked after, last at least 10 years. John

I don't usually use GOTO for the simple reason that my main scopes (14in Newtonian with Esprit150 piggybacked) are mounted on fork equatorial mount made by Astro Systems (Luton) in the 1980's, which doesn't have GOTO, and it would either not be possible, or prohibitively expensive to install it. It does however have a meridian pointer and large setting circles, which in conjunction with a sidereal clock (actually use an app on my phone now), I use to locate objects not visible to the naked eye, or Mercury and Venus in daylight. John

That's pretty much how things were 50 years ago in the 1970's, Fullerscopes and Astronomical Equipment (Luton) were prime examples, in fact they were just about the only producers of mounts in the UK, later joined by Astro Systems and Bedford Astronomical supplies. You could purchase the mounts with or without slow motions, synchronous motor drives or Variable Frequency Oscillators, or add them on a later date. Limited technology maybe, but no complicated motherboards to burn out. I have a 40 year old mount from Astro Systems, the original RA and Dec motors are still in working order, and touchwood will remain so the the rest of my observing days (I'm currently 73 years old !)

The Widescreen Centre , which I think is not too far from you, sell this eyepiece and illuminated reticle, both of which can be purchased separately. I have one of these, and touchwood not experienced any problems, changed batteries (LR44 I think) a few times TS-Optics 23mm 1.25" Illuminated Crosshair Eyepiece - Widescreen Centre (widescreen-centre.co.uk) John

Do you think that the rechargeable duster will provide a jet of air as powerful as the Kenair Air Duster, I usually get through one refill per year, and I notice that the cost of these on Amazon has now gone up to £20, and as you say the problem with these is that you have to be careful not to tilt them in use, otherwise propellant can get on your optics. I've just looked on Amazon now, and found a cheaper model at £39.99, don't know whether it would be as good as the Reesbi one, it says up tp 90000 rpm though. https://www.amazon.co.uk/Electric-Compressed-51000-90000-Rechargeable-Electronics/dp/B0BR9C7X6S/ref John

Looking at the above image, it appears to be out of focus, but at least the star images seem to be quite symmetrical discs indicating not a collimation problem John

I think that the William Optics scopes are generally regarded as being of better optical quality, and better engineered. John

Agree, I find that with the StellaLyra 30mm UFF in my f5 Newtonian, stars at the edge of the field are not in as sharp focus as those in the centre, not that they suffer from coma, but can be re-focused. With my Baader 36mm Hyperion Aspheric on the other hand, I get seagull shaped images at the edge, which cannot be brought into sharp focus, and which benefit from the coma corrector. John

I don't usually use a coma corrector with my f5 Newtonian, although I do have an Explore Scientific HR Coma Corrector, no doubt the results would be better if I used it, as I tried once with my Baader 36 mm Hyperion Aspheric, and it gave improved results. I don't usually use the coma corrector as its fiddly to use, and the weight of it causes balance issues with my fork mounted Newtonian. The whole point of getting the StellaLyra 30 mm UFF, was to get a well corrected eyepiece which doesn't require a coma corrector, I'm really surprised that you find that there is significant coma with your 30mm APM UFF at f6. Interesting that you find the APFOV to slightly greater than the stated 70 degrees, which is unusual, with most eyepieces the APFOV tends to be less than what is claimed. John

Ordered a StellaLyra 30mm UFF from FLO last week, and it arrived by express courier the next day, and since than have been able to try it out a couple times through my 14 in Newtonian, and overall quite impressed. As mentioned in another thread, I have been looking for some time for a low power wide field eyepiece that is both not excessively bulky and heavy, and will be sharp to the edges of the field of view in an f5 instrument, and the StellaLyra 30 mm UFF comes close to achieving both these aims. At 550g (not including lens caps, 570g with) it is no lightweight, but this is about 2/3rds of that of my ES 24 mm 82 degree eyepiece or 35mm Panoptic, and about half that of a 31mm Nagler, or a 30 mm ES 82 degree. Although the star images at the edge of the field of view through my f5 Newtonian were by no means perfect, they were noticeably superior to those in my ES 24 mm 82 degree eyepiece, and vastly superior to my 36 mm Baader Hyperion Aspheric. Although in the case of the former I was comparing an APFOV about 15% smaller, one thing I liked about the StellaLyra was that it had a sharply defined edge compared to the rather mushy edge of the ES 82 degree, and the whole of the field of view was immediately visible, as opposed to having to move the eye around in the case of the latter. If anything the claimed 70 degree APFOV of the StellaLyra was a bit on the modest side, holding the two eyepieces side by side, the APFOV was noticeably larger than that of my 24mm 68 degree Panoptic, similar to that of my 36mm 72 degree Hyperion Aspheric, and very close to that of my 17.5 mm 76 degree Morpheus. Before purchasing I was a bit worried that the actual APFOV might be significantly smaller that that claimed, as was the case with a StellaLyra 50mm Superview eyepiece that I once owned, which originally claimed to have an APFOV of 60 degrees, but turned out to be only around 45 degrees. With hindsight, I don't think that it is actually possible to produce a 50mm eyepiece with a 60 degree (or greater) APFOV in a 2in barrel. Furthermore at £179 (from FLO) the 30 mm StellaLyra UFF, although not cheap and having a smaller APFOV, is quite modestly priced being just over half that of a 30 mm ES 82 degree, or 1/4 that of a 31 mm Nagler. John

I thought that the whole point of the Petzval based FSQ series is that they have a built in field flattener, and that you don't need to use an additional one. John

If the mirror is about 10mm higher in the new cell than in the old one, then surely you would need about an extra 10mm of out travel on the focuser., which you can achieve with an extension tube if there is insufficient out travel on the focuser. John