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Xsubmariner

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Posts posted by Xsubmariner

  1. On 12/02/2021 at 09:04, SamAndrew said:

    Any advice on getting perfect balance? even with the motors disengaged on the Mk2 there seems to be quite a lot of stiction in the system,

    Great thread thanks Jonk and others for the information, you never stop learning.  Being told I have spanner hands, I generally struggle when a sensitive touch is needed so I acquired a cheap spring balance which works great for balancing these mounts.  As has already been said, both of mine have differing levels of stiction in different places as you rotate the RA & Dec axis even with the motors disengaged, but as Lucas says this is normal for these drives.

  2. Problem

      After building my new QHY 268M, CFW3-M  and OAGM setup I have been unable to get a guide camera to focus through the OAG. While the camera came with layout cards showing this setup for 55mm, I also hoped this arrangement would let me use my 3” flatteners (BF 52mm) with my TS&AA 130 triplets. Is it possible?

     Having attempted this setup my conclusions are:

    The minimum back focus (BF) this equipment arrangement can support is 54.5mm for a guide camera with 12.5mm BF. To achieve this BF the prism will have to be set at the very outer edge of the field of view. Note every mm the prism is extended into the optical path will necessitate the adding of a mm to the FW-OAGM spacers to keep the guide camera focus tied to the imaging camera and this will increase the overall setup BF. Whereas most OAGs keep the guide camera BF fixed while the prism is altered in the QHY OAG case it appears the guide camera is fixed in position and the BF is increased or reduced when the prism altered.

    The layout card for the above equipment included with the camera should show the additional spacers arranged between the CFW3 and the OAGM, with the exception of the 5mm M48 threaded spacer which stays in front to attach the kit to the flattener/reducer.

    The recent transition to short bodied cameras, QHY600M and 268M variant necessitates a redesigned OAG to deliver a short BF arrangement <55mm. 

    To use this arrangement with my 3” Flatteners I will need to either cut 4-5mm off the front of my Loadstar X2 or replace the 4 round head screws for countersunk units, and use a thinner M48 threaded spacer, say 2-3mm. This would recover 3-4mm and that is what I am planning to do, or should I just butcher my Loadstar X2?

     

    Back ground

      From what I have ascertained the minimum back focus distance from the centre of the OAG prism to guide camera sensor is 33mm + back focus of guide camera. This is based on assumption the adjustable prism is placed just inside the optical field of view to achieve the shortest possible guide camera BF. The 33 mm is measured from centre of the prism to guide camera housing base that the guide camera front face mates to.  A picture shows 30mm measured and there is 3mm taken up by material thickness and the 4 housing mounting screws with round heads ( countersunk heads could recover 1mm).

     The guide camera housing is 38mm deep and 39.5 with the 4 housing screws removed, so for the guide camera to reach the housing bottom the camera tube must be 38mm or greater.  This limited my choice to Loadstar X2, my GPcam 2 body was to short.

      My Loadstar X2 has a back focus of 12.5mm.  Therefore my OAGM minimum back focus is 33mm + 12.5mm = 45.5mm measured, but there is a practical need for some inward focus travel, say a minimum 1mm .  Moving the adjustable prism further into the optical tube to extend this distance risks covering or shadowing the APS-C imaging sensor. Retracting the prism to shorten the distance results in blanking a portion of the prism image. Therefore I assess the minimum OAGM back focus distance with a Loadstar is 44.5mm (C) . Noting there is 5mm from the prism centre and plus the 5mm thick M48 threaded spacer makes the minimum BF this kit can support =54.5mm (B) assuming you have the necessary 9.5mm spacers (A) available.

      To use my 3” flatteners with their 52.1mm (inc filter compensation) BF, I will need to reduce the OAGM BF by 1-2mm.  I hope to achieve this by swapping the round head screws for countersunk screws will recover 1mm and possibly shaving 1 mm off the Loadstar face. With FW-OAGM spacers (A) reduced to 8.5mm and the M48 threaded adapter swapped for a 3mm thick adapter I should be able to achieve a total back focus of 51mm, jod done. Now to find a 3mm thick M48 threaded adapter.

     

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  3. 18 hours ago, Deeko said:

     Coming from ZWO cameras I usually 'set and forget' to unity gain and default offset.

    That is the way I operate my ZWO camera’s. With the QHY you are given more control over how to tailor the cameras sensor data to your chosen target, whether this is a good thing or not, only time will tell.  Personalised offset and gain values can be stored with a title within the Driver for later selection.

    What would be beneficial is clear, unambiguous guidance on what startup settings the uninitiated user should adopt prior to developing their own skills.

    Have QHY already done this in the settings for DSO/Planetary that appear after  initially loading the driver software or were these values chosen randomly.

    I can find nothing to suggest they are recommended values can anyone enlighten me?

  4. 2 hours ago, Starflyer said:

    Are the M54 spacers threaded

    The only spacer that is threaded for M54 is this one and I measured ( engineers ruler) it at 4mm which isn’t aligned with the diagrams. 

    2 hours ago, Starflyer said:

    I thought the CFW3L was only available in 7 x 2", have they released a 7 x 36mm version?

    You are correct my bad, the filter wheel is the Medium not Large, was getting confused with my Q600 kit. Don’t seem to be able to edit the post at present to correct 🤔

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    • Thanks 2
  5.  

    2 hours ago, Simon Pepper said:

    Thanks Xsubmariner Are you able to recommend a cooled camera for my needs?

    It is always difficult to recommend a camera for other people as there are many factors that need to be considered. If you are able to buy new and your preference is for a cmos camera why would you consider a first generation unit with its known limitations when the second generation units are already available. The new 16 bit IMX based cameras are a substantial improvement in noise, QE and don’t suffer microlensing.

    If you are prepared to consider CCD as well as CMOs and used, there is plenty of choice and the market has been buoyant recently with some cracking cameras to be had.

  6.  

    8 minutes ago, teoria_del_big_bang said:

    What rotators are you using out of interest ?

    Hi Steve, I have a mix of Pyxis LE, Night Crawler and am currently fitting Falcon rotators which has been somewhat delayed as I chase short thread adapters.  The LE is limited as it can only be fitted to a 2” coupling, not ideal for imagery. The NC is integrated with the focuser as a package so limited to OTA by appropriate adapters. The falcon has M54 threaded input and output which integrates nicely with the emergence of M54 in the latest QHY kit and supports larger frame sensors. Unfortunately the lack of easily available thread adapters to connect the imaging components within short back-focus lengths remains a challenge at present, hopefully this situation will improve as M54 usage increases.

    • Thanks 1
  7. 17 minutes ago, Simon Pepper said:

    Thanks Nikolas. Perhaps I look at the 071 instead.

    Hi Simon the ZWO-071 is an APS-C size sensor with a pixel size of 4.78u, coupled with the Redcat 51 it will give you an image scale of 3.9 arc/sec per pixel. I have found an image scale of 1-2 arc/sec per pixel better suits U.K. skies. 

  8.  

    1 hour ago, teoria_del_big_bang said:

    Wow is that the 1600 next to it in the first pic ?   It looks tiny next to the new camera and filter wheel.

    Yes it is, as the pictures show the QHY camera and FW are substantially larger than the ZWO equipment.

    • Like 1
  9. Hi Guys the much waited for QHY268M has arrived along with CFW3M (7x36mm) and OAGM. The camera looks great and comes with the largest set of adapters I ever received with any camera. 

    It felt strange bolting the camera direct to the FW, but was much appreciated given the limited back focus I have with several Flatteners and Reducers. Within the kit 2 layout cards are included that show how to use the adapters to achieve a back focus of 55mm, with either CFW3M or CFW3L and with or without the OAGM.  I am relieved to see QHY have provided “real world” adapters with their camera that will allow most new owners to start using it straight out of the box.

    Having the camera secured to the FW will not be a problem for me as I have rotators fitted to most of my imaging equipment, though I can see it not being ideal for everyone. Cleaning the camera widow if dust settles will not be quick, given the FW has to be opened and carousel removed to gain access.  Should one experience dew on the camera window, I noticed a channel in the camera body to allow air to be blown in and a rubber bung fills the hole, when not in use.  I hope this information is of some benefit, now for some clear sky please.

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    • Like 5
    • Thanks 2
  10. Hi Neil,

    I don’t believe you can go wrong with the Mesu MK2, it is definitely a mount that does what it says, unlike some other mounts I have tried.  Your camera choice is interesting, while I have a mix of Cmos and CCD camera’s (QHY, ZWO & SX) my last three additions are all IMX455/571 sensor based units. These sensors offer considerable improvement over the older Cmos sensors and are worthy of some investigation.

    • Like 1
  11.  I suspect the 268M will come with the same spacer kit as the 268C, which is also identical to the 600L. While hoping to get the 268M next week, it’s unlikely I will get any imaging done as the sky here looks dismal for a week or so.

    The 268C doesn’t come with a tilt plate, it has a dovetail coupling to enable the camera to be rotated. I don’t like it much as it’s possible to off-centre the camera. Once I have the camera centred I only loosen one screw to rotate or remove the camera. I am thinking of using locktight on the other 2 screws.

    • Like 1
  12. Hi Neil,

    Welcome to SGL. It is a good time to get into AP, weather aside. Today there is a lot of choice with; cameras, optical equipment, mounts, capture and processing software. In fact so much choice that the first major challenge is determining what components support your individual needs. 

    This forum will provide access to a lot of knowledgeable people who will be able to support you in your first steps and beyond. Enjoy the journey.

  13. Stuart1971 “The Pegasus one is very good, so I have heard, but it’s wwwaaaayyyyy overpriced, as all the Pegasus kit is...”

    A review of rotators that are available today shows the Pegasus falcon is reasonably priced. Any commercial rotator has to be a precision instrument to support the necessary accuracy and strength criteria associated with the Astro imaging demands. Ultimately any failings in these areas will degrade the final image.

    Currently in the process of fitting a falcon rotator in my imaging system, thinking about rip offs in this community what about threaded adapters. I had to pay £145.79 for 4 x treaded adapters to fit the rotator, that’s a rip off. 

  14. Hi Desmond,

    I also have the L-Extreme filter and from my experience believe it is excellent for imaging with a colour camera when there is moon present (light noise swamps signal). I would definitely increase your exposure time when using the filter, remember you are effectively conducting narrow band imaging with a colour camera. Here is an image taken with my QHY163C with L-E filter on a 75% moon night. It is the combination of only 13 x 10 min exposures taken when clouds allowed.  Remember that your mount/guiding limitations will have to be adhered to, no point having more signal if your stars are bloated or misshapen due to poor guiding. 

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    • Like 1
    • Thanks 1
  15. There is a Dedicated  ZWO camera heater available that sticks to the camera faceplate and comes with a power splitter cable.  Wether to fit one or not depends on your environment and camera setup. Unless you are experiencing freezing moisture on your camera window I wouldn’t bother. I doubt ZWO would sell the camera dew heater that’s available if there was the possibility of damage to the camera.  If you are using a portable power arrangement it may be better to reduce the cooled temperature to -10 than add another power drain. 

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