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MarkS

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About MarkS

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    Melbourne, Australia

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  1. MarkS

    Fan speed

    Gerald, I can't answer you directly, as I don't have a DDM60 pro, but I do have a DDM85. I imagine that the fan control works the same. There are only the two connections on the 3-pin fan plug. The fan is controlled by voltage variation (I don't know if it is done by mark-space ratio or DC voltage adjustment, and I can't get to my gear to check). In any event the variation occurs within Autoslew. Have you tried re-installing Autoslew? If that doesn't fix it send an email to ASA Support - response is usually prompt. Mark
  2. I assume you are using CCDInspector to analyse for curvature. This may seem heretical, but I do not take a lot of notice of CCDInspector. I find it can give highly variable results - even within a single run. Having said that, there is always going to be some field curvature, and the FWHM of stars will deteriorate as you move out from the centre of the image. The deterioration may or may not have a curvature component. I find the most reliable - if very tedious - way to assess the image is by eye! (I produce my images primarily for printed display, so it's very important that the stars in
  3. The Cats Eye will give excellent on-axis collimation, even if the secondary mirror is not at the correct distance from the primary. So there may still be tilt. Only adjust two secondary screws at a time, and don't touch the centre screw. This will ensure that the secondary is only being tilted, and stay in the correct axial position. If the secondary has never been moved along the optical axis of the OTA, you should not have tilt problems (Unless the camera itself needs correcting. This can happen!) If the secondary needs re-positioning, there is an ASA document on how to get it right.
  4. I have not used my G4 with my ASA10N/ASA3" Wynne/AAF3, but I use a G3EC with external filter wheel with absolutely no problem. This camera weighs 2.9kg, whereas the G4EC plus L FW weighs 3 kg. So you shouldn't have any trouble. However, the ASA 10 alignment and collimation will be critical to minimising tilt. The dof for a f/3.6 scope is only ~+/-17micron. Therefore focal plane curvature plus tilt plus focus inaccuracy must be within a 35 micron band across the sensor dimensions. The axial position of the OTA secondary mirror must be spot on to take tilt out of the equation - it isn't goo
  5. I can't answer your question directly because I have no experience with 10 Micron mounts. However, I offer the following comments: 1. The ASA learning curve is perhaps steep, as the direct drive system is very different from others. I just threw away the old rulebook and started again! Balance and motor tuning are super-critical. 2. Some users seem to find the software difficult to deal with, particularly when trying to use it in conjunction with other observatory management software. Again I have no personal experience here. 3. There have been many software updates over the 7 y
  6. So you need a 14mm spacer to increase the backfocus distance. Then there is the matter of the axial position of the Parracor in the focuser to ensure you can reach focus. The ASA Wynne barrel design ensures this happens - you may need to experiment to find to right position for the Parracor. Mark
  7. Chris, Don't worry about collimation for the moment. The three images you present do not all show the same characteristics: I guess that the focus settings were not the same for each shot. However, the aberrations are roughly symmetric in each, and the CCDI image of curvature is symmetric. But the curvature is awful! I am not familiar with the Parracor, but I suspect that the backfocus distance of 57.3mm, which is correct for the ASA 3" Wynne (measured from the front face of the Wynne to the image plane) is not correct for the Parracor. I don't know what information is available for
  8. The ASA10N/3"Wynne does not vignette noticeably with a KAF8300 size sensor. I see no vignetting with a similar set-up, but I use 36mm filters. The adapter is 42mm i.d. When checking for ray path obstructions remember that the rays are converging. I suspect the filters may be too small. Mark
  9. Hi Nick, You have opened a thorny subject! Newtonian type astrographs are very difficult to collimate AND achieve coplanarity on the image plane and the sensor plane. All collimation tutorials that I've seen achieve collimation of the central ray, which is generally fine for observing, but the problem is that there are any number of configurations that will give central ray collimation, BUT ONLY ONE that results in coplanarity of image and sensor planes. The faster the optics the more critical the problem is because the focus depth becomes extremely shallow. In your case it is about
  10. MarkS

    NGC 6744

    Thanks for the comment, Michael. Much appreciated. Mark
  11. Hi Michael, I think what you are referring to is the "confirm each exposure" check box, which you will find in the Autopoint screen in the "Basic Pointingfile Settings" area. Cheers, Mark
  12. MarkS

    NGC 6744

    The southern galaxy NGC6744 lies about 30Mly away in Pavo. It is thought to be quite similar to our Milky Way, but is around twice the diameter at 200kly. It also has an associated dwarf not unlike the Magellanic Clouds. This LRGB image was shot over 3 nights using a custom Officina RiDK 300, Moravian G4-9000, and DDM85A. Processed in Pixinsight and Photoshop.
  13. Hi Andrzej I like this one! Great detail and colour intensity. Mark
  14. Why do you want to run AF with these filters? I have never tried to do this, but your problem is perhaps that there is not enough signal in SII and OIII bands of many stars. The usual procedure if your filters are not parfocal is to set focus very accurately (AF or manual) on L or R as a reference and then determine the focus offsets for the other filters. This can be done with careful AF or manual focusing on a suitable star field. There is provision in Sequence to record the offsets, which are then applied automatically to to the focus setting for each subframe. Hope this helps.
  15. '3560 image stars and 2860 plate stars' look way too many. Try limiting the magnitude ranges for plate solving to reduce these numbers. Refer to Sequence 200 Manual: 2.Settings Plate Solve. Mark
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