BlueAstra

SOLD

The Revelation RD003 0.75x Focal Reducer effectively reduces Revelation and Altair Ritchey-Chretien Telescopes from f/8 systems to f/6, increasing the apparent field and reducing exposure times accordingly. The 0.75x reducer also assures flat field and round stars edge to edge. The Reducer has a practical spacing distance of 80mm (+/-5mm) from the rear element to imaging chip, with an M42 thread if you want to use a spacer. Brand new, never used. Price £45 including postage to UK.

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I have the Evolution 9.25 with the Starsense camera. The OTA is large, but with the handle, manageable. I agree the tripod is sturdy but quite heavy and a bit awkward when you are lifting it into the car. I use primarily for visual or planetary/lunar imaging. You do have to check that the diagonal doesn’t clash at high elevations, especially if you are using Starsense auto-align. I sometimes unbalance it slightly forward to give clearance, the mount doesn’t seem to complain. I use a astrozap dew shield, I’ve never needed a dew heater strap. If you don’t use Starsense then you want a decent red dot finder.

Sorry I didn’t get back to you earlier, I missed the post. The bracket was made up from some pieces of Dexion (I think it’s called) screwed together, the sack trolly was from Costco. I drilled two holes in the trolly to mount the bracket. It was important to have some form of clip to hold the pillar mount in the bracket Otherwise it would slip out when moving. I don’t use this setup any more so I still have a spare trolly and pillar mount (but not the eq6) available for sale, although they are a bit scruffy now. I took part of the bracket off and would have to look for it now. PM me if you are interested.

I'm looking to change my camera mounted on an Esprit 150 to improve the pixel resolution (limit 0.77 arcsec) while trying to maintain FOV. I currently have an SXV-H16 which gives me a FOV of 0.83 deg and pixel resolution of 1.45 arcsec. I believe both the cameras quoted use the same chip and would give me FOV 0.68 deg and resolution 0.89 arcsec. Does anyone have any experience of these cameras, any preference between them, or maybe an alternative?

Here's the table for your scope:

The following table may help (values calculated for your scope): The Max A"*50 is the theoretical maximum magnification, the Max Dawes is a practical magnification limit. The exit pupil essentially tell you how bright the image will be, with a larger pupil letting more light into the eye. Note as you get older the ability to increase your eye's pupil size decreases.

For interest, this is two separate combined daytime images taken some years ago with my Canon 1000d and a lodestar guide camera, showing the relative field of view size and position. The OAG location is not perfect, ideally it wouldn't interfere with the main camera FOV. The OAG prism shouldn't 'block' any information from the main FOV, just reduce its brightness slightly.

I think I read somewhere that smaller apertures look through a smaller ‘plug’ of atmosphere, so are less susceptible to seeing effects. This could explain why the C5 looks better than the C9.25 if you have poor to moderate seeing. Conversely, the larger apertures would look better if seeing was excellent.

Another thing to note is that the SCT is a mirror system so doesn’t suffer from chromatic aberration. You probably need a triplet refractor to get minimal CA. Another difference is that SCT can need collimation, whereas refractors rarely need it.

Well, Takahashi have an enviable reputation for build quality and optical performance. Just check the camera is well matched in terms of pixel resolution and field of view. Its not very heavy so shouldn't need a particularly large mount. I would say with the right camera ideal for deep sky wide field photography with a portable rig.

For Sale - SOLD 10” Ritchey-Chretien Telescope Altair RC250-TT Truss Telescope with: Focuser tilt adjuster Primary & Secondary dew heater strap Mini dovetail clamp (for red dot finder) Starlight Instruments Feathertouch FTF-3015-B-A R&P focuser + custom adapter Baader Steeldrive focus motor Cloth light shield Mirror Covers Primary Mirror Fans Focus Spacer Tubes Dual Losmandy Rails Stock Focuser (replaced by Feathertouch) I got the RC250-TT from Altair Astro. Its been installed in my roll-off observatory since 2015. The observatory has heating and de-humidifier to keep storage conditions good. Collimation was good from delivery, and I’ve never actually had to collimate it. Mirrors recently cleaned. I’ve now moved to a wide field refractor setup so no longer need the telescope. Original price of telescope plus subsequent upgrades: £3255 Selling Price: £1700 If you don’t want the Feathertouch rack and pinion focuser I could remove it and re-install the stock focuser, but that may affect collimation and focus accuracy, especially under heavy loads. This would bring the overall price down to £1450 I also have a Takahashi collimating telescope (£175 new, never used, sell for £125) and a Revelation 0.75 focal reducer (£70 new, sell for £35) as optional extras to anyone buying the telescope. Would prefer pickup, meeting at a convenient location, or delivered personally if local as I don’t trust shippers to handle the scope gently. I’m located near Manchester. Graham

Apparently its a known bug. The solution is to type: cd "C:/program files/pixinsight/bin" (including exclamation marks) into the PI process console command line. In my case I had installed PI in the D drive of my desktop, which was probably the reason it couldn't find the files. I used "D:/program files/pixinsight/bin" which got it working on the desktop. I installed PI into the C drive of my laptop and Starnet loaded and worked OK without the fix.

Tried that as well and unfortunately still not working. The image is a non linear 24MB tiff file.