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bobro

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Everything posted by bobro

  1. Looks to be a standard EQ2 mount. The position of the RA flexible control relative to the eyepiece will vary depending on whether objects in the northern or southern sky are being viewed. Equatorial mounts are designed to be polar aligned to subsequently allow objects in the telescope's field of viewed to be tracked by adjusting only the RA control. This can be a bit tricky to understand but there are lots of youtube videos explaining this. Here is an example with an EQ2 (note this is for the southern hemisphere - for the northern hemisphere the RA axis is aligned with the north pole
  2. Here is a Youtube video that may help: https://www.youtube.com/watch?v=6Y0gU1YrnFM
  3. The dual axis motors are stepper motors, it's just that they are very low torque and highly geared to allow battery power driving without too much current consumption. I successfully used them connected to an AstroEQ for guiding. However, the gearbox makes slewing much too slow, hence they aren't good for goto.
  4. Some great things about the Moon are that it is easy to find and so bright that short exposure video imaging can be used with it. Many other DSOs, with the exceptions of planets, are dim and so require long exposure imaging. The dual axis motors, and mainly the RA motor, help with longer exposures though not with finding a target as they are too slow for goto. The dual axis motors can be used with guiding, though RA guiding mainly as DEC guiding isn't too accurate with the EQ5. So I agree with @SMF that the RA motor is useful and a low cost introduction to longer exposure manually located
  5. I purchased the Meade 130 Polaris about 3 years ago. It has 2 screws to secure the eyepiece (I added a third for imaging purposes). The aim of the red dot finder can be initially set using the 2 screws that attach it to the scope tube. Following that the finder adjustment screws provide fine tuning, with subsequent accurate pointing. Of course not everyone likes a red dot finder. It's a pretty good scope with an EQ2 mount having tubular legs, though still rather wobbly.
  6. Are you sure you mean the Declination ring and not the Right Ascension ring? The RA ring can be rotated if the locking screw next to the small pointer is released.
  7. I purchased one of these: http://ebay.co.uk/itm/223895728711 though from a different China based seller. Collimation as delivered was terrible, though the black (silicone?) stuff over the collimation screws was easy to remove, allowing the laser collimator to be collimated by projecting it onto a wall whilst rotating the collimator and adjusting the screws. A good purchase and did the job for my 2 scopes, which I thought were ok but turned out to be a bit off collimation.
  8. They are both equatorial mounts and can carry a DSLR. The Star Adventurer isn't GOTO, which can turn into a serious disadvantage: I upgraded from a guided EQ2 to a GOTO EQ5 mainly for this reason.
  9. An HEQ5 can make a great start to DSO astrophotography, especially where longer exposures and heavier carrying capacity are required. When imaging from a balcony there can be a restricted view, plus in the UK good imaging nights are few. That means capturing what can be seen as quickly as possible. One way to achieve this can be to go for brighter objects and/or widefield targets. This tends to mean shorter exposures perhaps with a shorter focal length scope and therefore a less capable mount can meet the need. One approach could be a Star Adventurer with a stock lens on your camera
  10. Also, what targets (e.g. Moon, planets, Deep Space Objects)? Astrophotography from a balcony in a location where there could be local light pollution may be challenging, though it does depend on the target and imaging method.
  11. A stretched version of the flat shows reasonably good collimation, but not quite spot-on. @tooth_dr suggests taking a photo of the setup (camera and CC attached to focus tube). This will help with a check of spacing (someone else will need to check this as I don't use the Baader CC). You could continue with a step-by-step check, with the camera next. When a 650D is astromodified the sensor is removed and needs to be refitted in the same alignment position. There are 3 screws holding the sensor - if they are not adjusted to the original position the sensor can be tilted, resulting in
  12. If polar alignment is well off it can result in stars showing as streaks, not as round out of focus stars. Holes in the centre of stars with a reflector are due to the secondary mirror becoming apparent with the image out of focus. With the CC removed, try taking a flat before imaging again. The resultant flat will show if the scope is collimated. The illumination source doesn't have to be too complicated e.g. an evenly illuminated ceiling without bright light directly entering the scope (what I use) or an evenly lit sky with a piece of paper or similar across the scope to diffuse
  13. You mention having cropped a lot of the image in the first post above. Even with cropping there is obviously something wrong with alignment as stars towards the bottom right are much less than sharp. With a coma corrector stars should be very much smaller. I suggest going back to basics. That means removing the CC and ensuring the scope is collimated. A flat and also an image of stars will help to show this - post here if it helps. If all is well the CC can then be added and flats etc redone to check the setup. It then should be possible to find out what is causing the glow if it still ap
  14. Measuring the amount of spare focuser inward travel available with the ASI224mc camera is straightforward: remove the eyepiece and stick a piece of white translucent paper across the focuser eyepiece flange. Then focus on a very distant object (the Moon is perfect, even during the day. Not the Sun). When in focus the image will be seen in focus on the paper. Now measure the amount of spare inward travel of the focuser. The flange to sensor distance of the ASI224mc is 12.5mm. Subtract this value (12.5mm) from the amount of spare inward travel previously measured. If the result is a positiv
  15. The beer can was for a bit of fun, but sticky tape does the job of adjusting height. Yes, a 130P reflector scope (various manufacturers) can be modified to come to focus with a DSLR. One way is to take a hacksaw to the tube, cutting something like 35mm from it at the main mirror end.
  16. Sometimes a weight can be improvised (the can is full of sand). Note - this image shows a DIY guided EQ2.
  17. Sounds like something isn't quite right with the setup. I started imaging with an EQ2 with economy motor and 650mm fl scope. Exposures of 30 sec were typical without star trailing with 60 sec on occasions. You mention exposures ruined by vibrations, so something must be causing vibrations. Is the camera shutter triggered remotely? Is the scope balanced (slightly east heavy in RA can help)? An out of balance scope could cause judder. My EQ2 mount settles within a few seconds of being touched, though it is the Meade tubular leg version rather than the SkyWatcher type. What about polar alignment
  18. Interesting thread. I too imaged with a Canon EOS1000D, experimenting with temperatures of over 20 degrees C. The amount of obvious pixel noise at higher temperatures was high, though I aimed for 20+ subs with dithering and used kappa-sigma stacking to eliminate a great deal of the pixel noise. Darks weren't taken. More recently I'm using an IMX183 mono uncooled camera. Due to the amp-glow darks are essential, with the darks eliminating the amp-glow and not being important in temperature for removing it. A couple of days ago I experimented with stacking an image using darks that were take
  19. Refractor telescopes bend light depending on wavelength. IR wavelengths can result in slightly out of focus images with refractors, hence the need for IR cut filters. Reflectors don't have this issue, hence an IR cut filter isn't so necessary to stop this. A CLS filter attempts to cut light wavelengths from local light pollution, so can be used for imaging galaxies where colour reproduction is important. UHC filters (not all are the same) limit wavelengths to the blue and red part of the spectrum. This is good for imaging emission nebulae as these produce mainly red and blue wavelen
  20. Here is a wip - 60 minutes taken this week with a 150PL f#8 on an EQ5. Camera is Altair Hypercam 183 mono non-cooled. Colour to come. There is obvious horizontal banding on the composite image, but isn't on all subs. A power issue perhaps? I haven't imaged that much with the camera, but this is the first time I have seen the banding.
  21. The 150P has a focuser with an eyepiece extension that can be unscrewed, allowing a DSLR to be closer to the OTA and achieve prime focus. A130P doesn't have a focuser that allows this, so the DSLR image plane will be too far away from the OTA and won't achieve prime focus. A Barlow can help, but has disadvantages as explained above. Shortening the OTA to move the primary mirror upwards, again as explained above, allows a DSLR to achieve focus. A well known issue with current 130P Newtonian scope designs when trying to get a mirrored DSLR to focus at infinity.
  22. That looks a really good capture at 4 min subs - good detail and nice round stars. Perhaps a bit too strong on the blue in colour balance?
  23. Although my CG5 (EQ5) is perhaps a bit light for carrying my 150/1200 PL for DSO imaging purposes (though that's how I use it), it is fairly solid and handles the OTA reasonably well for long exposure DSO imaging and should be fine for visual. Planetary imaging uses short exposures and is less demanding on mounts than DSO imaging. A suitable tracking (not goto) stepper motor for the EQ5 is: https://www.firstlightoptics.com/sky-watcher-mount-accessories/single-axis-dc-motor-drive-for-eq5.html
  24. Doesn't the 150P come to DSLR focus by unscrewing the eyepiece extender and attaching an adaptor as already purchased by the op? Removing the eyepiece extender brings the camera closer to the mirror. Same as on my 150PL. Not sure if it would work with a CC added though.
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