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Ade Turner

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Posts posted by Ade Turner

  1. Hi Folks

    With clear sky a rarity in the UK I’ve only just had chance to chase the comet C-2022 E3 ZTF.  I caught it on 6th Feb under a full moon, bortle 7/8 sky, light high cloud and in front of a very crowded star field all of which is making it tricky to process and I’m hoping for some advice please.

    I use Astro Pixel Processor, Affinity Photo 2 and StarNet v2. Although I know it’s very powerful I know I’m not going to get PixInsight - waaay to complicated for me. I followed the basic procedure in this video: 

     

    My efforts are in the attached photo sequence. I’ve done little additional processing to it beyond removing light pollution. My main issue is to find a way to minimise the ghost star trails on the comet plate (4). I used APP’s LNC MAD rejection set to 8 and 1.5 as suggested in the video, but honestly I’m not even certain what that means… Any suggestions which might help me improve this image? Thanks 😊 

    9D14C337-CFED-428C-A54E-D40307AFC1D4.jpeg

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  2. On 06/02/2023 at 20:19, MikeBY said:

    Keep the helical focuser.

    Remove the nosepiece and I/R filter from the ASI178. Thread the filter into the internal threads directly in front of the sensor.

    Remove the 1 1/4 nosepiece thumb screws on the helical focuser. 

    Thread the camera all the way on to the focuser and check orientation to the OAG prism. It should line up!  If it does not, get a very thin m42 threaded stop ring and thread it all the way on to the helical focuser then thread on the camera and back the camera off only enough to get it oriented with the prism. Tighten the stop ring against the camera to secure it to the focuser. Set the helical focuser to mid point (+4 mm).

    Note, the back focus of the ASI178 is split. The sensor is set 5 mm behind the front surface of the sensor window. The depth of the M42  threaded nose of the camera is 7.50 mm. 

    If the helical focuser's M42 threads are 7.5mm or more and the camera threads completely on, the minimum backfocus of the helical focuser plus camera is 37 +5 + = 42 mm. Maximum focus distance is 45 +5 = 50mm.  If a stop ring is used or the focuser threads are not deep enough you will need to measure this distance: The minimum depth of the focuser from the OAG frame to the front most edge of the camera and add 12.5 mm to get the this distance and add 8mm more to get maximum (8mm helical focuser range)

    The last adjustment is the prism depth.  It looks like the prism tube is fully extended. (6+14+6=26 mm). Focus distance (6+14 +0) = 20 mm.

    Focus range *fully threaded camera on helical focuser* is 

    62 to 70 mm  ( you can march focus with the main camera at 65 mm)

    However, the prism looks a bit low and may interfere with main sensor. Adjust it

    Loosen 2mm set screw(s) on the OAG frame that lock the prism in place. This may be in on the camera side or may be on the OAG frame edge.  BE CAREFUL. the prism carrier will be loose and can easily fall out. Do NOT TOUCH the prism. Surface! 

    Move the prism further away from center by 3 mm (shaft measurement now 11mm).  This puts the center of the focus range right at 65 mm.

    Focus main camera 1st. Then guide camera.

    Check for vignetting on both the main camera and guide camera. (During day) 

    Main camera vignetting, move prism away from center and refocus guide cam.

    Guide camera vignetting, move prism towards center. Refocus Guide cam.

    Tips:

    Be sure prism is perpendicular to the focal plane when adjusting length. Prism may extend into guide camera. if adjusted to high (large main sensors)  the top of prism may hit filter or sensor. BE CAREFUL.

    . If you have tilt adjustments, take test shots and adjust out any tilt. Tilt set screws can also be used as fine adjustment of Guide camera backfocus avoiding the 42mm stop ring.  Similarly some OAGs have tilt/stop screws to adjust the stop position of the  helical focuser where it threads on to OAG . 

    A note about your prism backfocus measurement point.  

    The image seen by the guider is refracted 90° by the 45° prism surface. The measurement point for focus is the plane of the image, which is the closest point to the camera where the 45° surface starts, not the midpoint of the slope. 

    Be sure everything is tight and lock the helical focuser. You should not need to adjust OAG focus again!  

    Worth the effort.. 

    If you switch to a DSLR the flange to sensor distance can vary slightly. Cannon EF is 44mm sensor to flange plus 11mm Flange to T2 adapter = 55 mm.

    Mirrorless is only 17.5 mm. to flange. However, if your buy the Cannon mirrorless camera T adapter it adds the 17.5 mm back in (it's 37.5 mm) to maintain the industry 55 mm standard. 

     

     

    Thanks very much Mike for taking the time out to give me such a detailed breakdown 😉

    I’ll work through it and definitely give it a shot. I’m using my 120 mini in the oag at the moment - it’s OK, it works reasonably well and I’ve had decent guiding but the sensor is tiny. It’ll be good to get the 178 on board and focussed.

    Cheers, Ade.
     

  3. 9 minutes ago, Stefan73 said:

    Wouldn't it be easier just to lose the helical focuser and use extension tubes / spacers to get the cameras parfocal?  You only need to get them parfocal once (and you can do it in daylight on an aerial or something).  I've never missed not being able to orient the guide camera yet for my OAG...

    Thanks Stefan, that’s an idea, thanks. I unscrewed it but I don’t think the thread is standard. It’s smaller than M42, around 38mm I’d reckon. 

  4. I’ve just bought a Celestron oag to use with my Edge 8 HD, 0.7 reducer, ASI 533MC-Pro (image) and ASI 178MM (guide). I’m having difficulty getting an equal distance between the cameras and the prism.

    I can easily achieve the required image camera back focus of 105 to within a gnat’s whisker (104.8). 

    The distance from the main sensor to the centre of the prism is 65mm. However, my guide camera sensor is 78mm to the prism, a 13mm difference. I’m assuming that’s too great a discrepancy?

    With the helical focuser already fully screwed down I see only two ways to reduce it:

    a) Remove the screw in IR filter and the nosepiece to gain about 2.5mm. I’m reluctant as then I wouldn’t be able to orient the guide sensor to the prism.

    b) Swap the 178MM for my 120MM mini which is only 8.5mm to its sensor. That would make the sensor to prism distance 74mm saving 4mm making the difference 9mm . But again I’m loathe to do this as I want to use the better 178MM to guide. 

    I’m still setting up in the house atm so nothing’s been tested.

    Any suggestions please? Thanks.

    4178ACA5-3829-45C6-B34A-70F692D3EB3D.jpeg

    61105AD0-7163-4FCC-ACDD-B153D9FC51E4.jpeg

  5. 1 hour ago, Cosmic Geoff said:

    I have never bothered my head about "back focus".  I use a CPC800 + Celestron prism diagonal + ZWO manual 5-filter wheel + ADC + ASI462MC for planetary imaging. 

    Thanks Geoff

    I’d always assumed/read that the camera’s sensor should always be as close to the recommended back focus as practical. Does it not make any difference then?

    You’re right about the 3x Barlow, it was a mistake I made a couple of years back but unfortunately I haven’t the funds to buy a replacement any time soon.

    My usual set up is for DSOs with the 0.7 reducer, chasing planets is pretty new to me and I’m at the bottom of the learning cliff 😉

  6. Does anyone have any recommendations for a short SCT/1.25mm visual back please?

    While Jupiter’s favourable I fancied trying my hand at planetary on my 8 Edge HD.

    Problem is my image train is about 30mm greater than Celestron’s recommended back focus of 133.35mm.

    The only element I think I can change is the visual back which accounts for nearly 60mm.

    My train: ASI 224MC > ZWO ADC > Celestron X-Cel LX 3x Barlow > Celestron Edge 1.25mm visual back

    TIA 

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  7. 13 minutes ago, powerlord said:

    I liked it so much I rewrote the manual for them (v2). I do see FLO still selling customer returns sometimes, so not everyone loves em - but for me once I got the hang of it I find them great. It's soo easy to just recheck em anytime once calibrated. I would suggest you read my manual a bit first before you buy so you see what it does (and doesn't!) do.

    https://www.firstlightoptics.com/other-collimation-tools/ocal-electronic-collimator.html

    v2 manual on that page.

    Sold! Thanks for the recommendation 😁

    I’ve watched a few videos now and can see how it works. Looks so much easier than fiddling on a freezing night with an unstable star image (bortle 7/8 round here, seeing is mostly abysmal).  And bye bye artificial star  😂

  8. 2 hours ago, powerlord said:

    a mirror ? stick it where scope is, and scope next to star. double the distance ? of course it'd have to be a good mirror - like a secondary mirror.

    Alternatively, I love my ocal collimator. use it to collimate all 3 of my newts and my C925. can be done inside, anytime.

    That should work but it would need to be precisely aligned - not sure I’m capable of achieving that, and I don’t have a mirror of suitable quality.

    Thanks for the tip about the Ocal though. Not come across it before. I’ve seen other more expensive solutions which rely on lasers but couldn’t justify the cost. This might do the job! Cheers 😉

  9. 2 hours ago, CraigT82 said:

    Did you need more outwards focus or inwards focus? Assuming outwards like with a newt when focusing on close objects so you can use an extension tube or similar

    Inward I think. The numbers on my EAF are decreasing so I assume inwards. An extension tube sounds like it could work to reduce the distance required, thanks, but wouldn’t that screw up my required back focus?

  10. Hello.

    I’m looking for suggestions please.

    I bought an artificial star so that I could collimate my Celestron 8 Edge HD in comfort during the day. I have a pretty long garden and set up my scope at one end and initially a bright target light on a step ladder at the other to get everything lined up. This was about 120’ away from the scope.

    I got tantalisingly close to focus, but it would simply not rack out any further. Sadly, I can’t increase the distance between scope and target. Is there anything else I can practically do to make this work please? TIA.

    Image train: 8 Edge HD > 0.7 Reducer > ASI 533MC

    EDIT: sorted now thanks. Just ordered an Ocal Colimator.

    779D7420-A5D6-4FAF-9815-A0946D38FF9A.jpeg

  11. On 09/06/2022 at 09:23, herne said:

    A simple, cheap solution I use is a personal attack alarm connected to a tripwire.

    The type of alarm used is where a pin is removed to set it off.  For example this (cheap) or this (more expensive).

     The alarm gets secured to something solid (I use a zip tie) with the tripwire (some fishing line) attached to the pin and stretched across a point of access.  For me, my equipment is set up on a raised platform which has railings all around it and a single set of steps leading up to it, so the tripwire goes across the steps.  I keep it at just below waist height to avoid foxes/cats setting it off.  A 140db alarm going off in the middle of the night will wake me up and (hopefully) scare off an intruder.

    If it’s not possible to stretch it across a point of access, it could be attached to the scope - one part on the scope, the other connected to the mount - or perhaps on a tripod leg connected to something solid (plant pot, nearby bush etc).

    Here’s a video to give you an idea of how it works:

    https://www.youtube.com/watch?v=XaQq2otgKH4

    Thanks for that - a great idea 👍 I like it because it’s less likely to suffer from accidental triggering. I’d probably attach it to somewhere on the scope with a pull wire into a ground anchor or the tripod. Maybe try and disguise it somehow so it just looks like another bit of Astro kit with a wire coming from it.

    • Like 1
  12. 4 hours ago, AbsolutelyN said:

    I have a 4k security camera pointing at where I setup, recording any movement 24/7. You can access it via phone so easy to check what's' going on from anywhere and setup detection alarms etc. Useful to check meridian flips etc never mind the obvious security implications. 

    I’ve Reolink PoE cameras covering most of the garden backed up with Arlo wireless. The Reolink images are great, very clear but their detection protocol is rubbish. The Arlo’s are the reverse - terrible image quality but brilliant detection and they’re well concealed. Together they compliment each other.

  13. On 02/06/2022 at 14:02, DaveL59 said:

    Not seen anything similar on sale recently, but place I used to live I'd fitted a PIR dual spotlight out front covering the drive, being 60ft it was useful to light the pathways to help find the way in the dark. Handy thing it also had was a plug-in unit for indoors that would activate with the floodlight, so it was hooked to a lamp which gave the impression to potential intruders that someone indoors was now also awake. Deterred a couple of stroll-ins to check out my car for sure.

    Something like this might work tho, PIR to detect movement and a light turns on indoors to deter intruders

    TC37- 110° PIR MOTION SENSOR TRANSMITTER AND PLUG THROUGH RECEIVER WITH GLOW LIGHT : Amazon.co.uk: DIY & Tools

    Not seen a combo like that before, looke interesting. At the moment I’m looking at the Switchbot system: Switchbot motion sensor

    I’m thinking of coupling up their mini pir mounted in a clear waterproof housing on the tripod to one of their mini button pushers to activate a wireless doorbell in the house. I’ve got the bits already for something else so I’ll experiment when I get chance 👍

    • Like 1
  14. On 30/05/2022 at 17:41, Clarkey said:

    I am obviously far too casual about this. I leave my stuff in the garden and go to bed. I have rain alarms but nothing else. Admittedly my garden is not easy to access and cannot be seen from the road, but maybe I should be more careful.

    I used to have a PIR in the garage which alarmed in the bedroom. However, it kept going off for no reason so I gave up on the idea.

    You know, I’d love to do just that and I’m pretty sure all would be well. We already have cameras covering most of the garden and in the 4 or 5 years I’ve had them we have never once captured any night visitors other than foxes, cats and hedgehogs. Having said that my paranoia tells me it’s only a matter of time…

  15. On 30/05/2022 at 16:23, Jiggy 67 said:

    I do think the nature of the equipment is a deterrent to burglars without the need for fancy defenses. Many burglars ( or trespassers in this case)can barely read, if they could they would have progressed to more lucrative criminality. I don’t think they would be able to dismantle my EQ6 R Pro in the dark and without making a racket and there is little chance of them moving it fully assembled. If they did get away with it, what would they do then??…they don’t know what it is. I think the average burglar would opt for something simpler like the garden shears out of of your shed…something they can sell for the next bag of weed! However it’s always possible……

    To be fair I struggle to dismantle my EQ6 R Pro in the dark too 😉 As you say, not the easiest thing to fence I’d imagine - and a lot of hassle to take it away.

  16. 2 hours ago, iapa said:

    I have 3 motion cameras in the Gard going full coverage of the area. There is also an Apple tracker thing attached to the mount., and the OTAs, in addition, my insurance cover includes specified items (description and serial number provided) kept outdoors against damage or theft.

    Me too on the camera front. A couple are Arlo wireless - awful bitrate and terrible picture but their detection is good. They are backed up by 4 PoE cameras which have brilliant pictures but rubbish detection - loads of false positives. Using them together gives pretty good coverage.

    I looked at Apple trackers - look useful and not too expensive either.

    The insurance angle is something I’ll need to look into, thanks for the reminder 😉

  17. 4 hours ago, Carbon Brush said:

    In my criminal experience. Oops choice of words. Experience of trying to keep criminals at bay....

    The first part is to let them know they have been detected. Something as simple as the motion detect lights that we all hate.
    As soon as they are over the fence anywhere in the garden, some distance from the scope, a light comes on.
    If the light is low power, like the solar powered lights, it is no trouble to install and not a bright nuisance.
    This may be spuriously triggered by a cat, or just a flaky sensor. But you don't lose hours of images.
    Motion sensors can have a short range radio link to a sounder in the house to disturb your slumber.

    If they get right up to the mount, it is reasonable to do more. A wire loop 60-90cm off ground won't be cat triggered.
    This can put on a big light and make a noise.
    They will either run, or grab something then run immediately.

    Finally fasten the mount/tripod to a ground spike and wire. If they make a grab, they won't get far and drop the scope before running.

    As a general rule, the villains don't mind lurking if nothing happens. But if they think there is some activity, they may look elsewhere.
    If there is a full blown 'lights and sirens' they usually could show Hussein Bolt a clean pair of heels.

    Another approach is to make removing anything a lengthy procedure. Not a single quick release.
    Why not replace the hand knobs to hold a dovetail in place by a allen head screws?
    It increases your build up/down time by less than a minute. But if you don't have an allen key....
    Something similar helps eyepieces stay in place on outreach😏

    HTH, David.

     

    Thanks David. PoE cameras cover most of my garden, some very visible others sneakily obscured, and I do have a bright IR lamp which reacts to motion 10 or so feet of the scope.

    The ground spike’s a good idea. I might sink a concrete block with a staple in the lawn under the tripod to accept a bike chain.

    I also like the idea of swapping out hand knobs for hex bolts. 👍 

    I’m not sure I’ll ever sleep easy whatever measures I put in place, but putting in measures to reduce risk of swiping will definitely help.

  18. 4 hours ago, maw lod qan said:

    Right now for me it's just a lock and dead bolt. But I worry to the point I walk around my property almost every morning from 2:30 am  to 4am.

    I make sure me and my bright white head lamp are visible while I'm out walking. 

    They hit my brother's 4 times. The last time all they stole was the motion sensor camera he set to catch them.

    I’d considered burying a concrete block and staple  to which I could secure the tripod, but the ota is still easy to remove.

    That’s terrible luck for your brother. I’m probably over-worrying, but the risk is there. 

  19. 40 minutes ago, Tomatobro said:

    If you don't mind a bit of DIY then a vibration switch can be soldered across the push button contacts of a wireless door bell and then fasten the door bell switch to the scope.

    The door bell can then be plugged into the mains so you get a warning if the scope is interfered with. This is the one I used from Ebay. The vibration switch also is available in various levels of sensitivity

    TECKNET Wireless Door Bells 400M Range Home Cordless 38 Chimes Plug In Doorbell

    That’s an idea, thanks! 👍

  20. 1 hour ago, PeterCPC said:

    I suggest just making access to the garden from the road as difficult as possible. I have a locked metal gate with barbed wire on top.

    Thanks Peter. Pretty much there on that front and fortunately our garden isn’t visible at any point for the road. However, some neighbouring gardens have easier access to the road than others so there’s always sneaky ways to get into our block.

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