johnturley

I found Dione difficult last night even with my 14in, as mentioned before I put it partly down to my deteriorating eyesight, although I have had a cataract operation in my (right), observing eye. Also I was viewing Saturn through some thin high cloud, and there was a not far off full moon not far away. John

If you are doing planetary imaging with a Canon 1200D (APS-C) sized sensor, I think that you will need to use eyepiece projection to get a decent sized image, a 2- 3x Barlow just won't give sufficient amplification. If the initial image size is too small, then you can't get sufficient decent alignment points in processing software such as AutoStakkert and Registax, a tiny image also makes initial focusing more difficult. When I used my Canon 6D (full frame sensor) with my 14in Newtonian, I needed to use eyepiece projection with a 12.5mm Plossl to get a decent sized image with Jupiter, and a 9.7mm for Saturn and Mars. I now have a ZWO 462 Planetary Camera, which has 2.9 micron pixels, but unless viewing condition are particularly good, I prefer to image through my Esprit 150 (fl 1050mm). According to the formula, the optimal focal ratio should be 3 x 2.9 = f8.7, but to give a reasonable image size even with Jupiter, I need to use a least a 2.5x Powermate giving f17.5. One observer on this site produces excellent nice sized planetary images through his C11 (fl 2,800mm ) and ZWO 462 at f20 (2x Barlow) , or even f25 (2.5x Barlow). John

Are their any experts on Stellarium out there, that might know whether it is possible to reduce the limiting magnitude of satellites, such as those of Saturn, displayed in 'Ocular View', so that in the case of Saturn for example it only displays the original pre-spacecraft 9 satellites, and increase the limiting magnitude of background stars stars displayed. I find it confusing that 'Ocular View' in Stellarium in the case of Saturn, displays lots of approx 15th magnitude minor satellites, which are not visible in amateur telescopes, but did not display a 12th magnitude background star that can easily be confused with a brighter satellite. I know that Stellarium does display background stars in Ocular View down to a certain magnitude, as the other week it did display the 5th Galilean moon that Jupiter appeared to have, (which was actually an approx 6th mag star in Aries), but did not show the 12th magnitude star in Aquarius, which was close to the predicted position of Hyperion. John

Me too, I don't know whether its a question of increased light pollution, or my deteriorating eyesight, or a combination of both, but in the 1970's with the 10in Newtonian I had then, I used to find Rhea, Tethys, Dione and sometimes Enceladus easy to spot. In recent years however, even with my 14in I've found Dione and Tethys quite hard to spot, and not seen Enceladus recently. For most of the 1970's though, Saturn was quite high up from the UK, so hopefully visibility of the fainter satellites will improve over the coming years, as Saturn moves higher up, and the near edgewise rings in 2025 will also help. John

Yes, almost certainly that star, thought it appeared far too bright to be Hyperion, which incidentally I've never been able to see visually. John

Looking at Saturn last night, I also could see Iapetus quite easily along with Titan, Rhea, and Dione. I could also make out what looked like a brightish 'moon' to the right of Titan (as seen in a telescope giving an inverted image), which according to Stellarium, roughly corresponded to the marked position of Hyperion,. However as it appeared only about a magnitude fainter than Titan, and brighter than Iapetus and Dione, I assume that it must have been a star (not shown as such on Stellarium) and not Hyperion. Did anyone else see this. John

Observed Saturn and Jupiter last night, viewing conditions were not very good and rather unsteady, I was unable to make out Cassini's Division on Saturn, but moons Titan, Iapetus, and Rhea were quite easy to spot, plus fleetingly I could glimpse what I think was Tethys, based on Stellarium. On Jupiter I was able to spot the shadow transit of Europa, but only when the shadow got to near the middle of the Jovian disc, I find shadow transits of Europa harder to spot than those of Io and Ganymede. John

Mike Did you notice a significant improvement in the planetary performance of the 100DZ over the 100DC, I'm inclined tp prefer the DZ, but I might consider the cheaper DF if there was negligible difference in the performance compared with the DZ. I assume the DF would be similar to the DC, and I did want a model with the larger focuser as I have several 2in eyepieces. Since the DF is f7.4 rather than the f8 of the DZ, I assume the tube will be about 6cm shorter, would this make the difference regarding aircraft carry on baggage. On the other hand I might not end up taking the scope on holiday anyway, in which case the DF would have not have any advantage over the DZ for me apart from saving about £600. John

According to FLO's website, they now have 2 FC 100DZ's in stock, so I assume Takahashi must have now overcome the problem of shortage of the relevant glass. Unfortunately RFVO's (and also Wide Screen Centre) website does not state whether they have them in stock, but I am assuming there must be a reasonable supply of stock available at present. John

Astro Trails are now saying on their website that there is limited availability on all their existing Mexico Eclipse Trips, although they they have now added on a 4 day 'Mexican Quickie', thought I would mention it anyone is still considering booking a trip. John

I downloaded Registax 6 on my Windows 10 laptop a couple of years ago no problem, I have MacAfee antivirus John

If I decide to get one, I would probably go to Rother Valley Optics who are nearby so that I could pick it up the scope in person, and avoid the risk of any damage or mis-collimation due to rough handling by the courier. I might also ask whether they would do a trade-in with my CPC 9.25 (which I purchased from them), although I suspect that any trade-in price would not be very good compared to what I could sell it for privately. I picked up my Esprit 150 direct from Es Reid after he had checked it over, so that I could be sure that this did not happen. John

FLO are still stating on their website that it can be carried out on most commercial flights, but I've had this contradicted from a couple of sources. They are stating currently out of stock, but available in 15-20 working days. Takahashi FC-100DZ (OTA) tube only with 50.8/31.75 adapter | First Light Optics

That's interesting, I have for some time been tempted by a Tak 100 DZ, which I would be able to fund if I sold both my Celestron CPC 9.25, and Explore Scientific 127 FCD 100 Refractor, which to be honest I don't use very much these days. In particular the CPC is getting rather heavy for me to move around these days at my age (73), plus my wife keeps pressurising me to reduce the number of telescopes in the conservatory (my 14in Newtonian and Esprit 150 are in my observatory shed). According to some posters the Tak fluorites perform like magic, permit 100x per inch of aperture to be used, and outperform other scopes of significantly larger aperture, in particular on planets. So like yourself I have been curious as to how one would perform, for about the same price as the 100 DZ I could obtain an APM 140 Refractor, which would almost certainly be superior to the ES 127, but less portable. The Tak 100 DZ, would however be a very high quality, plus much lighter and more portable instrument, and according to the spec I would be able to take it in the cabin on aircraft, although I have heard from a couple of sources that the latter in not actually the case. John

Arrived a few days ago from Amazon, a Reesibi Air Duster. Reesibi 90W Electric Air Duster Blower, Strongest 90000 RPM Compressed Air, Strong Blowing Force, Brushless Motor, 7500mAH, for PC, Keyboard, Car and Home Cleaning, Replaces Compressed Air Can : Amazon.co.uk: Stationery & Office Supplies I had been thinking of getting one of these for some time after reading a favourable review (I think on Cloudy Nights), with the intention of it replacing my Kenair Compressed Air Duster. What tipped the can however, was that I found out that the cost on Amazon of a replacement air cylinder for the Kenair, had gone up from around £17 to £24, plus Amazon had 30% off the price of the Reesibi, reducing it from £49 to £37, so I bit the bullet. I'm quite impressed with it so far, it is cordless with a built in rechargeable battery, and the air jet (which has 3 settings) is much more powerful than a hand blower, and almost as strong as the Kenair, but spread over a wider area. I used it successfully on my 14in Mirror yesterday, and unlike the Kenair, you don't have to worry about it depositing propellant (which is difficult to clean off) on the optics, if it not held vertically. Another risk with the Kenair, is that some years ago with an earlier model, the metal jet became detached and shot out at speed, which could have smashed a mirror or objective. The Reesibi unit will also be useful for drying off my mirror after a wet clean, last time I think I depleted about half a Kenair cylinder doing this. It comes with several attachments, including a USD charging lead and a brush attachment, which I shall not be using on optics, but may be useful for cleaning computer keyboards. John

Same here, had planned to view the GRS and Ganymede transits, but clouded out. John

If you look on First Light Optics website under ZWO Cameras, you can view the specifications of each model they stock, or drop them a line on questions@firstlightoptics.com John

Some ZWO cameras come with an all sky lens, not sure about the models in question. John

I haven't used my Canon 6D digital SLR for planetary imaging since getting a ZWO 462 Planetary Camera in 2021, if I remember rightly I think that I used around ISO 800 or 1,600 at 30 fps using eyepiece projection with a 9.7 mm Plossl. You get a lot more control over the settings with a dedicated planetary camera. John

I understand that the normal sporadic rate is supposed to be about 10 meteors per hour, so based on this the Perseids did not put on much of a display. John

With a digital SLR you will need to use eyepiece projection to get decent sized images that you can work on in processing programs, a 2 or 3x barlow won't give sufficient amplification, your 9.7 mm eyepiece, or with an APS-C sized sensor a 12-15mm eyepiece should work quite well. John

I think that meteor rates from the Perseids have declined in recent years, and its no longer the rich shower that it used to, I can remember there were good rates one year in the 1990's. John

Last night I made a comparison between my 17.5mm Morpheus and my 16mm Type 5 Nagler (82 degree APFOV) while viewing the M13 Hercules Cluster, the 2 eyepieces having almost exactly the same actual field of view, as the larger APFOV of the Nagler is more or less offset by the slightly lower magnification of the 17.5mm Morpheus. Both eyepieces provided a fairly sharp view across the entire field, but I found the viewing experience more comfortable with the Morpheus, and easier to view the whole field of view. In addition the Morpheus has a much more sharply defined field stop (appears bluish in daylight) compared to the Type 5 Nagler, where it appears quite mushy and yellowish (in daylight), similar in fact to what you get with Explore Scientific 82 degree series, and sometimes I understand referred to as the 'Ring of FIRE'. The Type 6 Naglers (which only go up to 13mm fl) on the other hand, have a sharply defined field stop similar to that of my 17.5 and 12.5 Morpheus (I assume that the others in the Morpheus range are the same). One advantage of the Naglers however, is that in 1.25 in barrels (including the 3-6mm Zoom), together with the 24 and 19mm Panoptics, they are all approximately parfocal, whereas the Morpheus and Explore Scientific 82 degree ranges are not. I find having a parfocal range particularly useful when viewing planets, especially Mercury and Venus in daylight. In short I use my Morpheus eyepieces more for deep sky objects, and the Naglers for planets. One recommendation I would make to all users of Morpheus eyepieces, is to fit the Baader M43 extension ring between the eyepiece and the rubber eyecup, as this largely avoids the large front lens element being fouled by grease from eyelashes.

I tried holding my 17.5 and 12.5mm Morpheus eyepieces side by side and the APFOV of the 12.5 mm does appear to be slightly larger. I noticed that when I got my Stella Lyra 30mm UFF eyepiece the APFOV appeared similar to the 17.5mm Morpheus, definitely not the 6 degrees smaller it would be if the APFOV of the 17.5mm Morpheus was the full claimed 76 degrees.

Observed Venus at around teatime yesterday, managed to locate it despite being only 5 days before Inferior Conjunction, in addition to the very slim illuminated crescent, I was able to make out the whole of the Venusian disc, which appeared distinctly darker than the surrounding sky. John