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Cosmic Geoff

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Posts posted by Cosmic Geoff

  1. The telescope is a C6 SCT.  You have the optical tube assembly (OTA) and to make it usable you need a 1.25" diagonal, an eyepiece (or preferably a set of three eyepieces of differing focal lengths), and a mount.  The choice of mounts is as wide as the sky. 

    This OTA was sold bundled with a SE mount, or an Evolution mount, (which cannot normally be bought separately) or an AVX mount (available separately).  Note that all of these are GoTo mounts.  It also seems to be available on a lightweight GoTo mount and a manual + platesolving setup (the Starsense app) none of them available separately.

    The OTA could go on a variety of Sky-watcher mounts. I'd suggest the widely available Eq-5 Synscan GoTo mount.   It could also go on a manual AZ-4 Skywatcher mount. (I have successfully used a 127mm Mak of the same focal length + AZ-4).

    Note that the prices of some of these mounts may come as a nasty shock.  I would point out though that you will get more out of the OTA, both for visual and for imaging, if you put it on a sturdy GoTo mount.

     

    • Like 1
  2. The ASI462 has a smaller pixel size, which gives a better match to a f10 SCT without using a Barlow lens (the best effective focal length depends on the camera pixel size).  I never had good results using a Barlow anyway.

    A consequence of the smaller pixel size is that planets look bigger on the laptop screen.

    With the same gain, the ASI462 offers shorter exposures - below 1ms on Mars and around 1ms on Jupiter.  

    The maximum FPS is not greatly increased (USB3).

    I used to process wholly with Registax, but with the ASI462 this gave rather bad results, and stacking with Autostakkert and final processing with Registax gives a much better result.  With the ASI462 it seems necessary to increase the colour saturation in Registax, otherwise the final images can look rather monochrome.

    It is essential to use an IR-cut filter with the ASI462 to get a correct colour balance.  I recommend getting ZWO's IR-pass filter as well, so you can take infrared images.  With the ASI224MC, the infrared images were often sharper, but with the  ASI462MC I have not so far found that the IR images are any sharper than the OSC.

    Overall I am satisfied with the ASI462MC and intend to use it for planetary imaging in preference to the ASI224MC.

    • Like 1
  3. Most people use an astro power tank, or a Celestron LiFePo power tank, or a car starter unit with 12v output (the latter unit is also useful for starting your car).

    The device you cite may be underpowered for a C8 SE and looks more suited for recharging mobile phones.  There was a thread on a similar topic recently, but I cannot find it right now. Also many previous threads.

  4. 1 hour ago, craftui said:

    I'm considering this Stella Lyra @cajen2 has recommended. But with 8.5kg weight it may be a bit heavy and awkward to mount and require a more expensive mount as @cajen2 has also pointed out.

    The listing says this is an imaging scope.  For that purpose it would require a substantial GoTo mount costing in the region of £1000.   The photo appears to show a large central obstruction.

  5. I doubt that a 102mm refractor would significantly outperform your present scope.

    If you are prepared to spend up to £1300, why not consider an 8" SCT? This would give a useful increase in aperture over your present scope, and be shorter and lighter than an 8" Dob, and in several of the standard packages would also have GoTo.  The Celestron SCTs are now quite expensive new, but there are lots of them out there and you should be able to find a used one at half the price of a new one.  This should be no problem if your budget is in fact £1300.

  6. On 04/10/2022 at 20:36, doctorbond said:

    May I ask two more things. The specific dell model you mentioned...is it just great value for money based on its age such as performance, or is it that but with other useful features such as serial port etc? I see it has decent spec for the money.

    When you say astro camera, can you help me a little more. Maybe a quick link so I get the idea? Do you mean something with a wire or a DSLR. What software would I start with?

    I

    The Dell Vostro is just an example.  (It happens to be the model I am using for imaging).  It's just a fairly up to date type with SSD instead of HDD, and USB3 ports, and consumes far less power than my older Vostro.  There are lots of laptops on Ebay as dealers buy business clearouts and sell them on. Any computer with serial ports belongs in a science museum. 🙂

    Astro camera - look up the details of the ZWO cameras in my signature.

  7. 3 hours ago, Kobayashi Maru said:

    I was considering the star travel 102 or 120. Here they come this the az3 mount which doesn’t seem to have a good reputation and can’t be used for EAA. How do you find the chromatic aberration? 

    Here the Startravel 102 or 120 can be bought as an OTA.  Apparently the AZ3 mount is one to avoid.

    The chromatic aberration is more visible in some circumstances than others - obvious when viewing the edge of the Moon,  not noticeable on images of galaxies.  Overall it is not enough of an issue to make me yearn for an ED or APO telescope.

  8. I had this 16/17 error twice with my Celestron SLT mount.  Briefly, it means that the handset is not seeing the mount electronics.   In my case the cause was that the mount firmware had become corrupted and required to be re-loaded.  The procedure for this requires a laptop, cabling with USB to serial converter that connects to the handset, and download of various firmware and utilities. (see nexstarsite.com for guidance)

    Also worth checking that the handset cable is firmly pushed into the (partly hidden) socket in the mount.  And that you have an adequate power supply and that the plug of any external power supply is making proper contact.   (Poor connection here is a known issue and it causes assorted problems).

    I recommend that you do not try using wifi until you have restored the outfit to proper operation with the handset.  If the mount firmware has failed, trying wifi will be a total failure.

    Also note that if you want to connect the mount or handset to a PC or laptop, you need to look up on nextarsite.com how this is done - it will not connect if you just plug in cables, and you might even cause damage. 

    • Like 1
  9. I use a 102mm f5 Startravel for EAA and find that it works fairly well for giving enhanced views with a FOV of about half a degree. 

    I bought a 50mm finder/guider with the idea of using it for plate-solve & re-sync alongside my visual telescopes, but I found it just didn't work unless aimed at a dense starfield like the Pleiades.

    A 127mm Mak should work for planetary (including imaging).

  10. The jump starters are relatively cheap, (often cheaper than a lead-acid 'astro power pack'), do the job and can also be used for starting your car, inflating tyres, and emergency lighting (depending on model).  They all seem to have a cigar lighter type output, and I doubt it matters much what model you buy for primarily astro use.

    I also have a Celestron LiFePo power pack, which was relatively expensive but said to be longer lasting than lead-acid batteries. It is light in weight for its capacity and also works well as an emergency light (good for working under car, or slug-hunting).   The output could be as much as 16v when freshly charged, but this has not been a problem in two or more years of use with three of my mounts.   The output will drop slightly if you don't use it immediately after charging, and will also drop a little under load.  The 5v USB output may also be of use to some.

    I would recommend either of the above for the O.P's rig. No need to buy anything exotic,, suspiciously cheap or any extra converters. 

    • Like 2
  11. Rather than answer this point by point, I would just say that when I first thought of buying my 127mm Mak SLT, I was thinking that I could fit an astro camera to it and view and control remotely...

    All this is more difficult in practice than it may seem to the uninitiated.   The SLT mount is not what I'd choose for a remote-controlled outfit.  I do have a setup that is capable of achieving the degree of GoTo pointing accuracy you would require for finding objects by remote control, but it relies on plate-solving (q.v.)

    The interfaces do involve RS-232 ports, but nobody uses computers incorporating these physical ports these days, and the relevant control port on my EQ-5 Synscan mount is physically a USB port, but still requires a special driver for reasons too tedious to describe here.  And it is controlled via Windows 10. Any recent laptop will probably suffice.

    The challenge is that Goto Mounts have a limited aiming accuracy, and astro cameras have a practical field of view that is often rather small.  Providing an astro camera that combines a large field of view (for finding things) with high resolution (for viewing fine planetary detail) could prove expensive.

    The view of a planet as seen via a live-view setup on a laptop screen will be familiar to planetary imagers - the view is surprisingly bad!  The detailed views produced by planetary imagers involve 'lucky imaging' (q.v.) via processing a video of several thousand images, and substantial post-processing.

    If this has not put you off,  I suggest that you acquire a useful laptop, e.g. a used Dell Vostro Windows 10 business laptop a few years old,  and an inexpensive astro camera. and try setting this up with one of your telescopes (without any remote control or remote viewing) .  The difficulties of your project will then become apparent. 🙄

  12. What are you trying to do with the boiling water? This will have no effect whatsoever on steel or aluminum sheet.  As suggested above, once you remove all the breakable stuff, steel sheet can be straightened out by panel beating.   Inevitably this may flake off some paint, and you will not get the shape perfectly restored.  Bending the metal in the opposite direction with that knob might help to straighten it.

    Steel will soften if heated red-hot, but there is no need to go to that extreme. 😁

    • Thanks 1
  13. 1. You can use colour (OSC) or mono, or mono with colour filter wheel - it's up to you.

    2. Most of the ZWO cameras have a 2" body, a detachable 1.25" nosepiece, and threads that match the common adaptors.

    3. What is a comma corrector?  

    4. Depends on the scope focal length, and the pixel size in your camera.

    5. I'd suggest a small pixel size. You do not need a large chip size.  A lot of people used an ASI224MC but now a ASI462MC seems favored, with even newer models coming. 

    You will also need an ADC (atmospheric dispersion corrector) for best results, especially if the planet is low in the sky.

    You could start by trying the ASI120MM - the ASI120MC wasn't a bad camera, and you won't need to guide for planetary imaging. 🙂

  14. What's your budget for the planetary imaging scope? There are lots of options. You need aperture, though in this country there could be diminishing returns in sizes beyond a C9.25, it seems, because of poor seeing.

    A 127mm would be underwhelming, but you could get the larger Mac, a Classic Cassegrain or a SCT (new or used).  For planetary imaging, you could choose anything that the HEQ5 would physically support for visual use.

    A Newtonian would be cheap but could prove awkward to use, partly because of the restricted focal range.

  15. 1 hour ago, Borderline Bob said:

    Any recommendations as to the camera,

    The ASI120MM will work, but the results will be mono (OK for the Moon).  

    I used an ASI224MC for a couple of years.

    I now use an ASI462MC which works well. It has a smaller pixel size than some other cameras (+less need for a Barlow).  There are probably even newer cameras worth considering.  You will need a UV/IR cut filter for this camera, and you may as well buy an IR-band pass filter as well for IR imaging.  You will also need an ADC (atmosphere dispersion corrector) for best results.

    I use an alt-azimuth fork mounted SCT. 

  16. 1 hour ago, Justi said:

    I've got the star adventure for quick setups. And have considered the az gti as another small option too. But often that tripod is in the car. 

    I have the celestron 4se but am wanting to upgrade this to ideally the 8se so can just switch out the telescopes but been waiting 3 years to see a used one here in Finland with no luck. But a cpc800 has appeared. 

    Which ideally would like to remove the telescope and just add my Solar Telescope to it for the Summer months but I don't think that is possible?

     

    Removing the OTA from a CPC800 is not something you want to do every day.   If you want an 8" SCT, the CPC800 is a better mounted scope than the C8 SE (which has the same OTA) but the outfit is much heavier. 

    I still think you should get a separate mount for your solar scope.  Why not use the mount of the C4 SE? It should take the weight and you can have the scopes on and off the mount in seconds.  I have had a 102mm f5 Startravel on my SLT mount.

  17. Out of interest I connected up my ASI120MC camera after a session on Jupiter with the ASI462MC.

    The processed results are not much different between the cameras (though the seeing was bad and none of the final images look sharp).  

    Found that with Sharpcap 4 the frame rate was a lot slower with the 120MC and the exposure time a lot more, and that the gain for the ASI120MC is variable, with the maximum being 100.

    I took a couple of videos with the IR filter and the ASO462MC, which clearly showed up a transiting moon (only its shadow could be seen on the normal shots.)

    With the ASI462MC,  5000 frame videos gave a notably better result than 2000 frames. (Finger trouble there).

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