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jefrs

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Posts posted by jefrs

  1. On 18/02/2021 at 21:36, Moodtastic said:

    Starsense does work with AVX. If you are doing visual then a rough polar alignment (I had the polarscope on mine) is all that is needed. Once polar aligned just set it off to do its thing and you will have pretty accurate go to.

    Yes it does work on the AVX. The StarSense camera and controller can support several different  mounts. StarSense is available for Celestron and Sky-Watcher but they are different flavours  and  are not interchangeable, (N.B.!!) 

    To align the AVX by the book - read the book of words (it is very tedious)

    Fist set up the mount pointing northwards (I'm North but your pole may differ).  Level the scope mount with a bubble, important! Roughly set alt and dec, I do mean alt & dec the mount screws - so the (optional polar scope ) tube is aimed somewhere near Polaris. See Polaris through the tube if your back will take it. I bought the polar scope, and a right-angle viewer, it is not needed.

    Enter time and date. Do set Real Time Clock (RTC) so it will remember in future. Set your exact lat & lon location.  Time and date must be correct, if it will not hold correct time and date  and/or your location change the backup CR2032 battery. 
    Always check the time before the off, the backup clock is as accurate as a cheap watch. If you use WiFi the interweb time servers synchronise to NIST so they should be accurate.  (Although NPL (UK) has the realisation of UTC and offers a time server too) .  You can select your time server on a computer but Microsoft gets its shorts in a bunch if it doesn't use their own)

    Now Align - Auto Align. It will slew to two stars and then want to Calibrate on up to a further four.  Follow the instructions on the controller.   It will slew to a star, align the OTA to that star. It will then slew to a second star, align the OTA to that. Now  it will want to Calibrate. It will display a list of stars that are up. Pick one you like, it will slew to that, follow instructions and centre on that. Repeat with three more.

    Now we want to do the Polar Align aka All-Star Polar Align. Press Align, find the Polar Align, select.  We are presented with a list of stars. We want one on the meridian, due south and fairly high, Rigel would be nice.  Select your star. It will slew to it. Follow the instructions on the hand set! First it wants you to centre the OTA to the star. Now it will slew off to where it thinks it should be. It will tell you to move the alt & dec screws to centre the star again.  Finish up. Polar Alignment done.

    But now it will want you to do another Align and Calibrate. This time however your corrections will be very small. The whole Align and Calibrate, centring the OTA on the star is boring! This is what the Star-Seance  does for you whilst you make a hot drink.

    Setting up the StarSense though  - read the StarSense book! First time is not just plug it in and run it. First time is Run it then Calibrate a few stars then run it again.  

    Imo the Align and Calibrate instructions in the manual(s) are not written in a straight-forwards "do this" manner.  Please make sure you read them forwards, backwards and sideways. The actual processes are nowhere near as difficult as the interminable instructions imply.  

    The StarSense takes the boring bit out of the Align and Calibrate. Especially with a stand-alone mount. If you cave cameras and computer there are other software methods of automating the job.    

    WiFi - if you have WiFi (who doesn't?) we can use the Celestron CPWI to run the StarSense Auto-Align then slew the OTA to target. Again there are other computerised methods available. 

    WiFi Sky-Portal v2. Issue as yet unresolved, Celestron tech are helpful but have yet to come up with a solution. This device is a WiFi dongle. The V2 is much more powerful than the V1.  First you connect to iPad/iPhone then tell it to connect to your home router and connect to Laptop. It will support more than one mount. You can run Celestron CPWI or other planetariums (I've not tested) to run StarSense Ailgn etc, and slew the mount about. using the planetarium, 
    Until your ISP gives you a nice new router!
    If you change the router name it will not connect to the new one and <rude-word> thing plays dumb insolence. It becomes utterly useless, I had to buy another.
    The V1 (which is not powerful enough for the range needed) has a reset hole, nice. The V2 does not (and there is no button inside 'cos I took it apart to find it). What you should do /before/ they change your router is switch the Sky-Portal back to iPad from the computer(!) and then delete the old router name from it, then give it the new router name from the iPhone.

  2. I have a T7C. There is also a T7M (mono). It is an almost-clone of the ASI120 MC (T7C with possibly a better sensor) and should identify as an ASI 120 for drivers etc (ASCOM   https://www.ascom-standards.org/ ). It works in PHD2, I use Windows though.  ZWO (ASI) drivers otherwise.

    Decent cheap camera. Don't expect too much. Mono would have more sensitivity for guiding but I also wanted to take photos without bothering with filters.  Guiding, moon, planetary, - deep sky possible. Decent digital camera and lens better for wide field. A decent digital camera mounted prime on the telescope will do a better job of imaging.

  3. The BT Home Hub expert I spoke to told me he used the mains plug in type himself.

    We have the BT Home Hub. The hub and two extender discs which can reach the garden shed 20m away. I had Netgear extenders as well but they interfered with the BT discs.

    The wifi dongle in the telescope needs to be quite powerful too.

    • Thanks 1
  4. Interchangeable OTA but keeping guider etc in place on the mount platten. Maybe like a side to side adapter but that would be overkill. Surely this has been done before?

    I'm not sure I am using the right language for search engines but I cannot find what I'm looking for. 

    This is a nuts and bolts problem.

    I have an AVX but it could be any mount.  I have a telescope. I have a guide cam scope. I have a Celestron StarSense alignment MacGuffin. 

    When I change the telescope the whole kit comes off, because it is mounted on the scope.

    Suppose I want to mount a camera and lens.  I may well still want the guider and StarSense, but there is nowhere to mount them.

    So what to do? The AVX has a combined Losmandy/Vixen which means I have a spare M8 screw hole to which I have  a dovetail clamp and a Y extension for the two devices. 

    This works but I cannot help feeling this has been done before and there will be a better solution.

  5. For say the Star Adventurer lifting a camera and lens - my heaviest outfit would be the Lumix G9 and PL100-400, total mass about 1.5kg. Adequate for the job.. For wide field, a much lighter lens. 

    If we are looking at astrophotography with a camera and lens - they're not all that heavy. With an Alt-Az though, you're going to get comma except with short exposures, which defeats the purpose of a motorised EQ. 

    You can spend a lot of money modifying a mount, it may be fun to do, but they are out there are reasonable prices.

  6. Old thread similar problem.  Clutch slipping. But not because the knob had loosened. I could not get the thing to align, the motors were running but the axes were slipping on the clutches.

    By tight I mean tight like gorilla, I know I can snap knobs off so I go easy on them, but they're tight.

    So I took it apart - There's a plastic button below the screw as a friction pad against a drum. Drum and button were slathered in grease. That is never going to grip.

    Presumably excess bearing/bush grease had oozed out making an unholy mess.

    The top dec  plate comes off the AVX, so it came off to reveal the drum.  Degreased by wiping in naphtha (Zippo lighter fluid).

    The bottom ra doesn't want to come apart, or at least not easily.  Degreased with WD40 ('orrible stuff) squirted in, not too much as I don't to wash grease out of the bearing/bush where it belongs. Then tissue wipe soaked in naphtha poked down the clutch screw hole and turned. A lot of black muck came out. Repeated a few times.

    (I often mix up the terms ra and dec because I don't need to use them to move the mount, forgive me if I've switched them about)

    Degreased the clutch screws and buttons. The dimple side of the button should provide most friction.  I roughed that side up a little on a fine file. A little, just to roughen it, not to remove material,  and washed off in the naphtha.

    Reassembled and arranged the knobs tight at ≥90° from stop. Frees off, locks absolutely solid with no undue effort.

  7. On 12/01/2022 at 21:05, the lemming said:

    I've got a Panasonic GH5 which I really like for video work, however it is shockingly bad with hot pixels for night time subjects such as star trails and the milky way.

    I'm very happy with the Micro Four Thirds camera system and I have invested quite a few pennies into MFT glass.

    I very much would appreciate recommendations of MFT cameras that can take good night time photography shots.

    I have no desire to go full frame.

     

    Cheers

    I've no desire to go to full frame neither. Mainly because they are not good enough for what I use a camera for.  Which is mainly wildlife where the crop sensor doubles the magnification (FoV) making the G9+PL100-400 a wildlife photographer's dream.   But I also shoot landscape and nighttime and use the cameras for astro. I've been using MFT a long time and cannot think of anything a FF or APS-C can do better.

    Most astro apps are tailored to the Canon EOS e.g. Backyard-EOS. However as Canon lenses can be fully adapted electronically to MFT, if you find you need to use those apps, a cheap used Canon EOS might make a useful secondary system.  Some used Canon can be had very cheaply, like under £50. I have considered it but so far not. Rather than Nikon which can only be dumb adapted.

  8. I'm afraid DxO smite MFT by correcting the low light (sports) performance for sensor size. If you know anything about photon sensor testing you know that is a massive no-no. There is even a code of practice that says thou shalt never, ever, never, correct for sensor size. To uncorrect the  DxO number multiply by 3.98 and you will see they are a lot better in low light than FF sensors.

    Several reasons. The smaller the size, the less heat produced, the less noise. LMOS sweeps stray electrons off the sensor, CMOS does not. Smaller size, less read noise. MFT can shoot video at night in a tent lit by a candle, news reporters have relied on that.

    The Lumix G7 and later Lumix have "Starlight AF". It can AF on say, Jupiter.  You won't have AF with it on a telescope but it does mean the focus peaking will work reliably.; Jupiter is not at infinity.  By default Lumix NR is a bit too aggressive, turn it down for less artefacts. Whilst the G7 is not as cleaned up as the G9, it's not speckled like the G5.  Whilst the G9 does not have "Dual Native ISO", it does have a step in its ISO range which makes ISO 12800 as clean as ISO 6400 by trading off dynamic range. Compared to the oldest digital cameras I have ISO 20,000 on the G9 is more than acceptable.

  9. On 09/01/2022 at 23:36, the lemming said:

    I have a MFT camera and an assortment of filters for it. I mainly use my ND filters for video work during the day, but a filter that greatly reduces light isn't a good idea for night time photography.

     

    What useful circular "screw on" filters would be a good for simple subjects like the moon, landscapes or time lapses of the stars?

    I have a 1/4 Pro Mist filter for video work and it does a very good job at enhancing sunset videos by giving the sun an extra glow and pleasing colour vibrancy. Probably not so great for pin point stars.

    SLT have a range of Clip-In filters for Olympus and Panasonic. I.E. have filter and prime mount on OTA. They are not the same fitment. I use Astro-Multispectra to reduce town lights. Depends on your Bortal.

    You can get the astro filters screw on but as they are expensive it makes no sense if you ever consider mounting the camera onto a telescope,

    An ND makes sense for moon photos. You can get clip-in ND and coloured filters too. It is very bright and we want a DoF of 1,700km, so we want a smaller aperture. However MFT tend to do better wider than f/13 - f/16 and f/22 tend to produce aberrations. You can get around things but spot metering highlight on the moon and superimposing a nighttime foreground metered there on long exposure (moon blown out).

    Lance Keimig  "Night Photography ..." ISBN 978-0-415-71898-1

    The Auto-WB and exposure metering goes to pot with the moon.  The metering tries to adjust to 18% grey but the moon is not grey, and the sky is not black.  Much of it is grey but also sandy-gold. If you let these cameras do their own thing you can get a daylight blue sky at night.

    I do still use polarising and Wratten 85, The latter more to take the sting out of flash and warm it up. I used an 81A "cloudy" to warm sunsets on film,  The 82A "Morning and Evening" is bluish and does the opposite. The AWB may knock the WB back to midday sun temperature. The colours can be pushed about in the Lumix Photostyles, but not like the PEN-F where every colour can be adjusted to emulate film stock, or such that never existed. I've got ND, never had much use for them. I've played with coloured grads, a bit meh. Nota, the Wratten 85 is a proper film conversion not a typical Orange 85 but more subtle; 85B is bright orange, 85C is "Dawn & Dusk" but the 81/82 series are light balancing, amber 81A provides subtle warming. Coloured filters were more for film but digital can usually push the colours about by fiddling the WB or Photostyle.

  10. On 12/01/2022 at 21:05, the lemming said:

    I've got a Panasonic GH5 which I really like for video work, however it is shockingly bad with hot pixels for night time subjects such as star trails and the milky way.

    I'm very happy with the Micro Four Thirds camera system and I have invested quite a few pennies into MFT glass.

    I very much would appreciate recommendations of MFT cameras that can take good night time photography shots.

    I have no desire to go full frame.

     

    Cheers

    I've been using MFT for many years and surprised the GH5 is giving you hot pixels. You have fixed that :)

    Cameras I have and have used on OTA - G5, G7, E-PL7, E-M5ii, GH4, G9, PEN-F.

    SLT clip-in filters for Olympus and Panasonic.  Astro Multispectra. Much depends on your Bortal.

    Some pros and cons.

    The G7 and E-PL7 are lightweight

    From G7 on, Lumix have "Starlight AF". With an AF lens they will focus on Jupiter or the moon. On an OTA we don;t have AF but it does mean the focus peaking works,

    G5 does not have focus peaking. But does take good images, it shares sensor with the GH3.

    The E-PL7 has the same innards as an E-M10ii

    The PEN-F and G9 are 20Mp, probably the same sensor, like your GH5. We do not need the extra pixels but they are newer tech, quieter, more dynamic range.

    The E-M5ii shares innards with the PEN-F but 16Mp.

    The GH4 is one big heat sink, the sensor does not get hot.

    The key point of the G9 is its ridiculous stabilisation, we do not need stabilisation on a tripod

    Back focus can be an issue mounted prime. I had to get a couple of different extra-shallow T2 to MFT adapters.

    MFT doubles the magnification like a X2 Barlow, reduced field of view, may need a reducer.  Advantage less edge curve.

    There is no Backyard-EOS for MFT. Olympus Workspace is good for Olympus but Lumix Tether not so much, nor the wireless phone apps for them. They will not allow more than 60s exposure

    Default NR can be too aggressive ans remove faint stars, Long shutter NR is a dark frame subtraction, how much it does can be adjusted and is good for single shots but a waste of milk for stacking.

    All native MFT lenses are "good". Some are more equal than others.

  11. Do not buy cheap and nasty.  Or something that needs three more parts of equal expense to make it work.

    For simple astrophotography with camera and lens, the Sky Watcher Star-Adventurer with a hefty photographic tripod (Manfrotto 055XPROB or similar). . With that you get the wedge, the motor, the mount, polar finder, and counter weight.  And it is relatively light and portable.  About £330 quid plus about £150 for new tripod. Eats batteries and wants a power supply.

    Latest version comes with wifi. I cannot think why you would need that on this.  It can be guided but not really needed because its motor is good and it's only got one axis to control.

    It is simple. It works.

    • Like 1
  12. On 23/05/2020 at 22:54, JOC said:

    I haven't waded through tbe rest of the answers, but my telecope has a focal length og 1200mm.  I always assumed that if I put my dslr into the focusser with no other Eye piece in place that it was like stcking a 1200mm lens onto the DSLR

    That is exactly right. It's a 1200mm lens on your camera, any camera.

    We focus an image circle diameter of  the diagonal of the sensor.  It has nothing to do with pixel pitch, it's an optical image size. With crop sensor cameras we often refer to equivalent length to full frame. On a MFT with a x2 crop factor the 1200mm lens will be /equivalent/ to 2400mm on full frame. It's properly called field of view.  I hate using "equivalent focal length", it's a poor term.  The image circle diameter is smaller thus reducing the field of view. In other words, the moon looks bigger.

  13. The StarSense is brilliant for alignment, once its initial set up is done.  I found mine needed focussing to solve maximum number of stars. Which meant moving the focus in and out in ever decreasing little turns whilst running alignment over and over again. After the initial Auto-align it then needs calibration - do read the instructions. Calibration aligns the camera to the OTA. It is not a guider, it is a goto alignment tool.

    It is a Celestron device, there are Celestron and SkyWatcher flavours, they are not interchangeable.  

    Once set up operation is very simple, you just push the button. Full alignment may only take a few minutes. A lot easier and less painful than squinting at a red dot or finder scope and then trying to put the star in the middle of the eyepiece (what is an eyepiece?). It will also polar align to aid you setting the manual polar alignment screws. 

    If StarSense is run by wifi it will get lat/lon and time from the computer.

  14. A Power Tank battery that seems on its way out may be recharged with a Noco Genius G3500 which is a small intelligent charger for motorcycles. It is a 3.5A charger but has a 1A setting for small batteries as used on motorcycles, and in the Power Tank. To charge the Power Tank connect to the red and black screw terminals with the Power Tank set to OFF.  The G3500 will indicate when the battery is fully charged.

    Small lead acid should not be charged at more than 1A rate. Use the 1A AGM battery setting. Do not use any 3.5A setting. The G3500 is far more 'intelligent' than an optimiser. It also has a recovery mode that may bring a lead acid back from dead.  Please note I use the word 'may' here and above, if the battery is completely dead it will not work; I have recovered a deeply discharged but fairly new motorbike battery that has continued to work perfectly.  A charged lead acid 'in storage' should last up to six months without any current drain; I have a reminder set up for every two months to check all lead acid and lithium batteries, and recharge as required.  Lead acid batteries do not like being on continuous charge (small current), nor being recharged too often; but they do like being fully charged (full current) when they are recharged; leave them on an intelligent charger for 24h.

    If the Power Tank battery is dead it will not recharge.  It is a fairly standard burglar alarm type leisure battery, replacements can be obtained from the usual suspects online.

    Perhaps keep the Power Tank in the car plugged into a lighter socket so that it charges whenever the car is running, as the car's own battery does. Not into an always-on socket that may drain the car's battery.

  15. I have StarSense from my 130SLT on which it is very good and takes only a few minutes, and which I have just fitted to AVX and waiting for clear sky to test.

    Reading the StarSense manual the sequence is to AutoAlign first (no I do not know why as it is going to need Auto-aligning again after polar align is shifted) then Polar Align upon which StarSense will give instructions on how far to Manually move the mount up or down, left or right, to align Polaris. Note - Manually using the big screws, not the motor controls.

    The StarSense has to be calibrated to your OTA, it does not know where your OTA is pointed. To aid doing this I first align RACI crosshairs to the centre of the OTA, which can be done in daylight. This process is described in the StarSense manual - StarSense will move to a star and tell you to align the OTA centre to the star and save the position. (my OTA will be loaded with a camera and I cannot use a red dot, RACI is easier)

    The StarSense /must/ be focussed. Which is not a lot of fun as there is no camera output. So you have to run alignment and iteratively move the focus in ever decreasing turns back and forth to gain maximum star numbers during plate solving. This can take all night but once done is done. When done StarSense will align very quickly, a few minutes.  If it takes longer it needs focussing.

    Once the first Auto-alignment is done StarSense needs to ba calibrated per the manual. StarSense will also plate solve during the night to aid GoTo alignment.  It is a GoTo aid and will allow you to hit the mark accurately. StarSense also likes additional calibration points, and to know which areas it should not try to use (like the side of the house). What it is not is a star guider. It takes the hard work out of aligning a computerised mount.

    StarSense is very easy to use in practice, you just hit the button to align. Once it has been set up, that's is. It is worth having; the mount will not work without alignment, StarSense does that for you. But you must read and understand the manual first, and the manual is written backwards and sideways.

    • Thanks 1
  16. Rotate the OTA in rings so you can access the eyepieces. I have a RACI for alignment calibration of a StarSense which is all pretty heavy so I position to counter balance the camera i.e. along the top of the Newt.  The AVX mount doesn't seem to mind the slight sideways imbalance.

    Why are EQ mounts always shown with the telescope facing Polaris? They're never used like that. Rotate the Newt in its rings  to where it is in viewing position.

    I also use Micro Four Thirds (MFT) cameras. The G9 is not small, it is heavier than the half-brick GH4 whereas the E-M5ii is small and light, which itself is heavier than the DMC-G7 (I've been acquiring them for years). What we can do is fit a not cheap but worth it clip-in CLS filter (STC Astro Nightscape) to knock out most but not all of the annoying terrestrial lighting.  (I'm Bortal 4/5 but with a problematic (cof) 'shielded' streetlamp).  The usual T2 to MFT adaptor is probably loo long, the depth of a DSLR light box, so a thin one is needed on the focusser. If the focusser is swung below the OTA the weight of the camera can drag it out making focussing a pain.

    Unlike Canon we don't have BackyardEOS but can cable tether to either Panalympus apps, but they're far from ideal for astro. So we have to rely on the cameras, which are excellent and have built in interval timers to 1 minute exposure. Using them on wifi makes them get hot and is a bit of a waste of milk because so many functions are missing from the fondle slab app. They will also focus-peak on e.g. the moon, which helps. NR needs playing with to stop it removing faint stars.  Olympus will get a hot battery, use their power supply, but Panasonic have effective heat sinks.  The G9 eats more battery than the GH4 which has the best heat sink, but then a used G7 may be had cheaply and is very light.

  17. A CLS-CCD filter is for a modified camera with no IR filter, or an astro eyepiece camera. They can be fitted to an eyepiece and some Barlow, or the T-adaptor for the DSLR.

    I have an Astronomik  CLS-CCD on a T7C guide cam, eyepiece screw-on. It made a significant improvement. The sensor lacks filters and the firmware of a DSLR. Using that filter with an unmodified DSLR produces rubbish results, a lot of colour shift.

    A DSLR needs to be set up for astro and night photography. They will get rid of a lot of the rubbish which an astro cam relies on a laptop app to do. The auto WB usually works. A lot of the NR needs to be reduced (or it will remove faint stars). The contrast and sharpness needs to be fiddled with. Any auto exposure will be way off.  AF won't work on stars unless you have a Panasonic, new Olympus or Pentax.

    I have the STC Clip Astro Nightscape Filter clipped into my Olympus E-M5ii. It did not make a significant difference however we are Bortal 5 going Bortal 4 but with a LED streetlamp nearby.  LED lighting is difficult to filter out. For more Bortal you may well want the heavier Multispectra filter cf (scroll down) https://shop.stcoptics.com/product/clip-olympus/

    But, big but, clip-in filters are expensive, they are good where you are using a camera lens, they also shield an otherwise open sensor mounted prime on a telescope. They're also camera specific, the Olympus clip-in will not fit my Panasonic, nevermind. You may want to save the money and spend it on an astro camera for a telescope; then you also want filters.  I do mount the Olympus on the telescope or with lenses.

  18. The 130SLT is not a bad telescope but the best thing about it is the mirror, The focuser wants to be taken apart, cleaned and serviced; some soft grease used, and the tension adjusted so it moves smoothly. The nylon bars on the slide may want packing with tape to reduce slop. The focussing is rack and pinion, and quite coarse, but by adding a long lever to one of the knobs, such as a battery crocodile clip can move it in small doses. Have the lock screw just touching whilst focussing to reduce slop, nip it lightly once in position.

    The problem with 'back focus' (which means something else to photographers) aka 'flange focal distance' means the camera needs to be moved in or out from the the eyepiece/Barlow. Typically the sensor needs to be at the distance your eye would be.  This may be done with extension tubes, an eyepiece projector, longer or shorter camera adapters, or even a focussing eyepiece adapter. A DSLR has a mirror box, a mirrorless camera does not, an eyepiece camera (ZWO etc) can be moved on its stop ring. This distance is not super critical as then the whole lot is focussed on the telescope.  Experiment.

    The 130SLT eyepiece adapter may even be fitted on the underside of the plate, allowing a Barlow or nosepiece T2 adapter to drop further inwards, saving that the clamp screws are too long and would have to be replaced with shorter ones or grub screws. I've tried this with the screws out, loose, it kinda works.

    An Olympus E-M5ii can for example achieve prime focus mounted directly on the 1.1/4 eyepiece adapter of the 130STL with a thin T2-MFT adapter; most MFT adapters have an extension tube to allow for the missing mirror box when adapting a camera lens.  A different length tube may be needed to mount it onto a Barlow. Tubes and adapters are available in different lengths.

    The NexStar 130SLT does not have powerful motors and cannot support much weight on the nose of the OTA, a suitable tube ring may be used at the back end to counter balance the additional mass.

  19. First of all StarSense is an alignment tool. There are Celestron and SkyWatcher flavours. It connects by the ST4 port to the mount, it does not /need/ a laptop. It does have a USB port but that is /only/ for firmware update. With the firmware updated and its camera focussed (which is a royal pain) it can align and calibrate the mount in 15-30 seconds. Seriously, it can be that fast but it does have to be focussed. As such is it a very valuable tool for aligning the mount. The only way I could focus it was a boring iterative process of screwing the lens in an out a little at a time to find maximum stars, it took all night.

    It can be operated by software, Celestron provide apps for laptop (USB) or fondle slab (WiFi). If USB then that is the one on the StarSense handset. I do not know about the StarWatcher version. The iPad app has poor controls, very jerky, but that may be the WiFi. The Celestron laptop app "CPWI" is very good.

    It does not star guide as such but during the course of a night it will occasionally go into plate solving mode and realign/recalibrate. Thus StarSense should be left connected during the course of the night. It aligns by plate solving. Thus it maintains accurate tracking, but it does not guide the mount on a star, you would need an additional star guider for that. 

    I have tried to get images out of it but to no avail, its USB port does not transmit image data. Its ST4 port is only for guiding the mount. If it did have a proper camera output that would be a great boon for focussing; there's a missed trick here. But using it as a guide camera might interfere with its auto-recalibration routine; it's a one-purpose device.

  20. Chinon (Japan) could make exceptional lenses to rival or exceed Asahi Pentax. Very good glass that will probably exceed Olympus and Nikon. I have a pair of 8x40 wide angle 9°.  Chinon produced the first production autofocus camera lenses. Chinon got bought out by Kodak Japan.  You should be able to compensate vision on one of the eyepieces. You may want to use a monopod or video head tripod when looking up for long.

  21. On 24/05/2020 at 12:44, Adam J said:

    People always get this wrong and say it's 4/3 of an inch diagonal...which it can be in some cases but it's actually the aspect ratio. 

    That is incorrect. It does have a 4:3 aspect but not why it is called 4/3-inch, It dates back to steam powered TV cameras and the internal diameter of the tube (valve) used in them. It is just a name. Rather like incorrectly calling full frame DSLR full frame when they're the same size as compact film. Image circle diameter of 4/3 is 21.6mm, less than an inch.

    Something to note though is a smaller sensor does not receive less light than a large one. When they are pulled into focus, all the light from the lens (telescope) is focussed upon it. What is important is the photoreceptor (pixel) size. A larger sensor can have larger pixels but on the down side they become slower to transfer data, harder to keep cool, and are noisier.

  22. On 24/05/2020 at 10:47, spikkyboy said:

    Can somebody tell me what a 4/3 sensor is and what the pros and cons of that would be? Thanks

    The name "4/3" comes from the size of a TV camera tube, now pretty much obsolete. The image sensor of Four Thirds and MFT measures 18 mm × 13.5 mm (22.5 mm diagonal), with an imaging area of 17.3 mm × 13.0 mm (21.6 mm diagonal), comparable to the frame size of 110 film. (wiki).  Micro Four Thirds (MFT or M43) is actually the lens fitting, the sensor is "4/3".  The image circle diameter is almost exactly half that of  a full frame camera, so the crop factor is X2, which effectively doubles the length of the lens, or telescope.  The pixel size of the 16MP sensors is 3.75µ (slightly larger than most APS). but the 20MP sensors have smaller pixels.

    For example - The £700 ZWO ASI294MC Colour 4/3"  has a Sony 4/3 11MP CMOS sensor with 4.63µ pixels. The earliest MFT cameras were about 12MP.

    The MFT cameras have a Live-MOS which unlike a CMOS is biased, this reduces electronic noise. Some are made by Panasonic and some by Sony, but to Panasonic design. It is not unusual for a rival to manufacture parts.

    Being mirrorless MFT cameras only have a live view, which can be boosted for faint objects to aid focussing. Or dimmed right down for the moon.

    Recent MFT cameras will wifi to iOS apps on fondle slabs to control and view images However some of the functions are then missing and probably not suitable for astro. Both makes will shutter to 1 minute and have intervalometers, Lumix ASCOM  drivers are available to wifi to laptop, however in my feeble efforts these appear clunky, the wifi keeps falling over.  iPads only have a single wifi, so you cannot get GPS and time from the interweb when connected to the camera. The higher end cameras can be tethered to a laptop by manufacturer or third party applications. What you get in a MFT camera is a very good sensor and a powerful processor that can interval shoot long exposures to JPEG+RAW and optionally compile to movie, and do its own dark framing better than most software.

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