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Jessun

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Everything posted by Jessun

  1. Hi! Yes many use a reducer on RCs. F8 is generally considered slow. Well at least sluggish. A common reducer for the 8" is one made by Astro-Physics. It's a 0.67 which would bring your RC down to f5.36. This will make your exposures 2.2 times faster. Why is it faster? Well because your RC - like many designs of course - will collect light and concentrate that to a circle of focused light at the back where you put the camera. If you held a piece of paper there if would look like a circle, bright in the middle, fading towards the edges. The reduced sits in front of the camera and it will catch light at the periphery that would otherwise have missed the camera. More photons will hit the camera, but ONLY because you're now gathering light from a bigger patch of the sky. So you're not exposing anything quicker per se, you're just looking at more sky. Your objects/targets will be smaller too which may not be what you desire but it's all a trade off. On the plus side is that if your sky quality is bad then this will appear as a grainy busy background around your target. Unwanted signal basically in a somewhat random pattern. It helps to have many exposures to even this unwanted signal when you stack in order to get rid of it. The more exposures the better. Some swear to see improvement up to 100 exposures or 'subs', whereas the maths suggest that the gain of more sub exposures fall rather quickly. As you process the images, stacking etc, personally I found it easier to work with a bigger number of exposures. And easier equals more fun. As to dew heater, it really depends on the ambient air. It can't be ruled out that one night you would have benefited from one. Many high end RCs have this as an option. But save the money I'd say. A dew shield on a closed tube will help, but again it all depends on what the air is like. And how often it's damp enough to deposit. It's a cheaper solution but then makes the setup more prone to wobble if there's a wind.... It's an eternal game of compromise! /Jessun
  2. In short: Yes it's good. It screws straight onto the drawtube of the focuser and leaves enough back focus to fit filter wheel and camera. Or a DSLR straight onto it without filter wheel. /Jessun
  3. Hi! I'm not much of an observer but bought this for my Skywatcher ED120. Perhaps the scope didn't quite do the Pentax justice, I really don't know but it any case it quickly went back in the box and has been there for years... I'm sure if you're reading this you know this line of optics from (former) Pentax, but here's a refresher simply copied from the web: "With unsurpassed optical clarity and a short focal length, the XW 5.0 offers a 70 degree field of view for easier viewing. All of our eyepieces are constructed with a high-refraction, low-dispersion lanthanum glass that consistently delivers bright, high-resolution images with minimal distortion. In addition, all XW series eyepieces are built to JIS Class 4 weather-proof standards which increases their durability in less than ideal conditions. Designed for use with a wide range of telescopes and PENTAX brand spotting scopes, the XW series eyepieces are a clear choice for ground and astronomical applications. Pentax 5mm XW Eyepiece - 1.25" Improved 70 degree field of view for wider views XW 3.5mm, 5mm, 7mm, 10mm, 14mm, 20mm, 30mm, and 40mm provide a wider field of view than previous PENTAX eyepieces All Pentax XW series eyepieces may be used with astronomical telescopes with appropriate 1 ¼” or 2” focusers. XW 3.5mm, 5mm, 7mm, 10mm, 14mm, 20mm eyepieces may be used with our PF series Spotting Scopes (except PF 63 Zoom) Full multi-coated lenses increase light transmission and contrast High refraction, extra-low dispersion lanthanum glass elements deliver bright, high resolution images with minimal distortions and aberrations Advanced computer simulation design technology implemented to drastically reduce internal reflections, producing brighter, clearer images Weatherproof construction for greater durability Long eye relief for comfortable viewing with or without glasses Pentax Product Number: 70512" The unit is in great condition. Stored in room temperature in its boxes. Price £190 ONO SOLD Hope someone can make use of it! /Jessun
  4. These worked fine for me in my triplet: http://www.teleskop-express.de/shop/product_info.php/language/en/info/p6983_Baader-M68-Zeiss-Gewinde-Schnellkupplung-und-360--Rotation.html Rotating the scopes in the rings work too I suppose, just a lot more effort with three.... /Jessun
  5. Guys, don't make me keep it :-D
  6. Haha, well, I'm an uneducated observer. I looked at Saturn once and then the Moon a couple of times but that's it... But yeah, I did my research before buying it and it's up there for sure.
  7. I'm with Sara here on the car analogy... BUT you can crash in a car. This hobby is safe, wont rust and friends and others are genuinely interested in what you're doing. An oldish Maserati GT in a garage can only ever be just that. /Jessun
  8. Hi! Geoptic dual vixen saddle: 320mm * 100mm. CC between Viven bars about 210mm. The saddle itself needs to be bolted to another plate to fix to a mount. £42 SOLD Pair of guide rings: 100mm - good for up to 95mm guide scopes. Nylon ends on bolts. The bolts tighten with a 4mm allen wrench. Each ring is flattened to allow for secure one bolt mounting to a plate. I think it's M5 or M6. £37 SOLD Altair Astro blue anodized Vixen saddle. As per Altair specs but some noticeable UV discoloration. Function not affected of course. £15 SOLD Farpoint FDUP black 14" Losmandy plate. Has one visible mark from a bolt in the centre slot. Otherwise mint. £20 SOLD I'll aim to ship from the UK so tracked postage is included for the UK. I just don't like to have stuff like this in storage when it should be used. At present not listed elsewhere. /Jessun
  9. Hi, no I really couldn't tell, or even guess. Plenty of these reducers out there though so search around for someone who's actually tried it. /Jessun
  10. Newbie alert was quickest to jump on the Farpoint chaps. /Jessun
  11. Hi newbie alert. Forgive me but I don't quite understand the question. If you mean the Farpoint then here's a link that may help :-) http://www.highpointscientific.com/farpoint-universal-dovetail-plate-fdup
  12. I have a monorail focuser on the RC. It's an Orion one, but they are fairly generic I'd say. Mine seems loose, and I can wiggle the drawtube sideways - it's like it's pivoting over the point where the rail meets the friction screw. It's a full millimetre each way, and that makes for quite a bit of angular movement for such a short draw tube... Not good. Can this be adjusted? Greatful for any advice! /Jesper
  13. SOLD I never used this. Instead I sold the RC it was intended for.... SO it's been sitting in its box unused. It has one visible mark on the front at 5 o'clock, a small scratch (see image). That's all. New this kit is £245 or thereabouts. Grab the kit here for £200 :-) /Jesper
  14. Jessun

    Aligning camera in RA and Dec

    I simply turn the camera as best as I can to align it. Then I pick a bright star and expose whilst slewing. The trail will tell me how to adjust. I always have North up. No reason for it whatsoever, just my way of doing it - it just matches my mental picture of the targets I suppose. This means that my M31 is often said to be up side down... You can't win! /Jesper
  15. Hi! I'll leave visual work to others as I know nothing about it. For imaging, the scopes you list are all very different. Looking at imaging, I'd start out with working out your seeing and then look for a camera/OTA combo delivers close to that number. You mentioned the Sony A7 and again I know nothing about this one, but I can quickly Google a pixel size of 5.96 or 4.87 microns - correct me if I'm wrong. Those are good numbers, middle of the field really and lends itself to many scopes. Then download this tool or similar: http://www.newastro.com/book_new/camera_app.html In there you can play around with cameras and scopes etc, and you can put in the Sony details, and then change the focal length to match your seeing. Let's say you settle for something like 600mm to 900mm. Well, then the next question is how fast you want to image. Keeping the focal length fixed, as you open the aperture the faster the exposures. Money disappears almost exponentially as f-ration goes down... And so do all other problems with focus and collimation etc... The other parameter that plays a huge part in imaging is of course CCD/CMOS chip size but with the Sony you will enjoy quite the field already. Back to the Sony, again I know nothing about it, but I have seen quite a few threads about it on SGL. Perhaps there are other cams that can compete. /Jessun
  16. Atik 460 sale pending - NOW SOLD
  17. PS, will be listed elsewhere within days.
  18. Thank you Olly! I really can't wait to see what you can do with your kit down at Les Granges! So here again is up for grabs (an Atik 460EXm SOLD camera) and an EFW2 wheel with a 9 filter wheel for 1.25" mounted filters. I'll start with the bad bits. I have cut the power cords to both the camera and the filter wheel since I can't stand the cigarette plugs that were on the other end. You will need to add some length of cable i.e. solder it on and isolate to mate with a power source plug of your choice. I will try to find the cig plugs to make the purchase somewhat more complete, but pleeease don't use them. Ever. :-) The good bits: The camera and the filter wheel comes delivered as you would have had them delivered from Atik. (OK, I admit, that in one of the images a tiny clothing fibre has landed inside the camera opening). In other words these units have NO signs of use. NO signs of UV discoloration and come with ALL that you'd expect to find in the boxes. They were always kept indoors between sessions. (I used to roll out and set up each night). The EFW2 has serial number 3W14120828. The unit is one number away from the units Olly just bought with confidence. The camera in the listing has achieved the following btw: AAPOD 12 DEC 2015 AAPOD 23 SEP 2014 AAPOD 18 AUG 2014 AAPOD 26 MAY 2014 AAPOD 21 APR 2014 AAPOD 23 MAR 2014 Plus publishing in Astronomy Now, and featured in The Sky @ Night magazine and online. The ATIK460 hits a sweet spot for many. It's easy to use and whilst it doesn't cover the greatest field and doesn't cool as good as some, it sure does deliver. The EFW2 integrates well with available software and never misses a beat. Beautifully crafted and finished. Below are some images of the actual units. All the best fellow imagers Prices again: Atik EFW2 9 position 1.25" - €350 Atik 460EXm - €1500 SOLD /Jessun
  19. What format are you saving them as? Do you get the same thing with the EOS and the Moravian? Nice kit by the way! /Jesper
  20. Jessun

    Extensions for M48

    Some more options here although I don't see a 7mm piece. http://www.teleskop-express.de/shop/index.php/language/en/cat/c124_Verlaengerungsringe.html You could use two 3mm with a 1mm ring between them perhaps. /Jesper
  21. Can this upgrade be retrofitted by the user? Not to argue, just curious about all good mounts out there. /Jesper
  22. Not an awful lot of interest here or elsewhere for the APMs. So I'm pulling them off this listing. Look out for the cameras and filter wheels on other sites. Cheers
  23. Yes Stuart, of course there are other parts in a traditional worm and wheel mount that will rotate at a higher rate, but as the torque drops on each part so does the price of that same part. I've had a free gearbox upgrade, but Roland and his team have since developed a new gearbox which I believe is metal all the way. It has other cool features too. I could buy these units now and have them delivered within a week or so. Being a modular design that lends itself to end user bolt on upgrades I thinks AP can't be discarded from a European perspective. What is the smallest piece of the Avalon that could be shipped back and replaced by the user? Are they even working on upgrades or just a complete new mount? I really don't know and I'm also not on the AP payroll. It matters nothing what anyone uses really so long as it all works. I just wouldn't worry to much about getting an AP. Several are in use on the South Pole... Pretty far away from your average Postman Pat van for replacement parts. /Jesper Below is a clip from NEAF 2016 with Dennis De Cicco. Just some new stuff. It's all really good, but I don't need any of it. I just roll out once in a blue moon, setup from scratch, and I'm only subjected to the drift of the clock in the handset. If it's off by a second per month I just have to redo a fix on a star and that's it. The star will be close to the cross hairs anyways. For me, guiding does the rest.
  24. All I can add to this, having had no hands on experience with either, is that I wouldn't worry about getting the AP. I have the 1600 and I have enjoyed superb support directly from AP. (And Baader here in in Europe for that matter). I had a chip upgrade sent with FEDEX at no cost, and a gear box upgrade sent again at no cost. Any mount from AP since 1998 can be upgraded with their latest GTOCP4 control box allowing for WiFi etc. I always refer to my 1600 as the gentle giant. It was never the issue when it came to imaging. Everything else was. Remember also that it's a modular unit. You will at most send one faulty part back if there is one. Not the whole thing. One final note is my personal view on wear. I think wear can be dismissed entirely. Let's say you live on the equator and enjoy 12 hours of imaging every day of the year. By one year your mount will have made about 183 revolutions if all you do is tracking, carrying a well balanced load with the resulting forces on your lithium greased gears approximating zero. OK, start your car, let's say it's a diesel and it will idle at about 1000 rpm. The engine rotates under constant ignition shocks, and in just 11 seconds it has done your 183 annual revolutions. Every minute equates to almost 5 years of mount use... It's true of course that we don't ask for the same tiny tolerance in our car engine, nor the precision of the revolutions, but that's why we guide or use a sky model. To correct these tiny errors. The sky is often a greater problem than the mount's accuracy. /Jesper
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