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Ricochet

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Posts posted by Ricochet

  1. I would rent both scopes, the C6 to be used visually whilst the Vespera is stacking subs as an EEA device. This way both scopes give instant gratification during the holiday compared to astrophotography where all you might be doing is gathering data to process once you get home (aside from the issues with the unsuitability of the scope and mount).  Additionally, I would rent the scopes this week as well as next so that you can get used to setting them up and check that they work correctly before you are on holiday. 
     

    With regards to additional eyepieces something like an 8-24mm zoom will work well in an f10 scope and should be available at a reasonable price. This should give good lunar views as the moon will be dominating the skies during the holiday. You should also get/make a dew shield for the C6 as the exposed front corrector plates are prone to dewing. 

  2. I don’t find tracking with a dob that difficult a task so I suspect that something with a push to system like the Starsense dobs will be fine instead of a full go to system. With regards to size the weight can be off putting long term so a dob without motors might get more use. Ed Ting estimates that once the initial excitement has worn off an 8” will get used twice as often as a 10”. 
     

    I also suspect that this is something best not given as a surprise as your son may already have his own idea as to which direction he wants to go in terms of upgrading. 

  3. 1 hour ago, TiffsAndAstro said:

    Omg Ty so much :)

    Your focus knobs axis is 90 degrees to your dovetail, like how mine arrived in the case but I rotated the tube rings so they're not as in pic below. 

     

    IMG_20240405_185011.thumb.jpg.e87a64816f0d95d6860223afda09573c.jpg

    It's ok for me to do what I have, right?

    Yes, you can have the dovetail in any position you like. Mine sits on the right because I use it visually on an alt az mount where the scope sits to the side of the alt axis. 

    • Like 1
  4. As the tube is rolled steel perhaps some magnets could be epoxied to the bottom of the Telrad base to help it stay put. However, from memory the Telrad base has a V-block profile to allow it to be used with a variety of different sized scopes. With a 12" dob the arc of the tube under the Telrad base will be relatively flat so perhaps the problem with the original/replacement sticky pads is that there is only a very slim area of contact along each edge of the base. In this case you could potentially make some sort of adaptor or fill some of the space under the base to create a larger contact patch for the sticky pads to stick to.

  5. I use Vixen SLVs (9/6/4) with my Lunt 50. If you end up double stacking there is an off axis reflection you want to keep out of the field of view, so wide angle eyepieces can be a hinderance. In addition, there will be a sweet spot in the centre of the fov which shows more detail so you will always want to be observing on axis. 

    I can also recommend the R-sky observing hoods that FLO have recently started selling. I bought a white one, the only concern is how a large white hood looks to anyone else, so the black might actually be preferable. 

  6. You’ve not included what I consider to be a vital piece of information, the focal ratio of your telescope, so that we can consider the question in terms of exit pupil. In my opinion the most important (DSO) eyepiece in your set is the one that produces an exit pupil between 2mm and 2.5mm with your telescope. I believe that your telescope is f/8.6 so the eyepiece that I would spend the most money on, and plan the entire eyepiece set around lies in the range 17.2-21.5mm, so in this case yes, you do need to add an 18.2mm Delite to your collection. However, in my f/6 scope the 13mm would generate an exit pupil in the 2-2.5mm range and so the 18.2mm would only be a luxury eyepiece rather than a necessary one.

    • Like 2
  7. 17 minutes ago, Mr Spock said:

    I suppose for me the best mid range eyepiece is the Nirvana. I'm looking at the moon tonight with my 12" and the 7mm Nirvana for x217 and it's very sharp and contrasty. Plenty of detail on Jupiter too. Remarkable for £85 https://www.firstlightoptics.com/ovl-eyepieces/nirvana-es-uwa-82-ultrawide-eyepieces.html

    Note: the 16mm is pants.

    I think that is the range I’d be looking at too. I’d probably start with the 10mm for the 10”, 13mm the 8”.

    I saw a 28mm pop up on eBay a couple of days ago for £150 which would be a great choice for (almost) maxing out the fov.

  8. Black stalked 9x50 RACI

    White stalked 9x50 RACI

    Same finder, different  colour scheme. Pick the one that matches your telescope best if you're bothered about that or whichever is cheapest. The Astro Essentials version is available bundled with a foot if you need an additional foot for a multi-finder setup - assuming you can fit it to the telescope.

    On the filter front, I consider the Baader Neodymium a good planetary filter but I cannot recollect a single DSO that has been improved by using the filter.

    • Like 2
  9. 40 minutes ago, dweller25 said:

    @Nikolai De Silva

    I would suggest before you change the collimation screws that you do a star test first to see if it needs adjusting.

    If it does here is what to do…..

    IMG_1055.jpeg.751a99980d5732a35d8c34fe0d042ca0.jpeg

    Some points on this:

    • A star test must be performed with an eyepiece with a focal length equal to or shorter than the focal ratio of the telescope
    • The star must be precisely centred in the field of view and stay centred during collimation. A off centre star looks the same as a uncollimated scope. For an undriven scope this means using Polaris, which at only 8° Nikolai may not be able to see.
    • I believe the above instructions apply to adjustments made to the primary mirror, which cannot be adjusted for the scope in question.
    •  Based on experience, never attempt to adjust the secondary using a star test, it will not go well.

    Given the above, I would suggest a quick star test is a good way to check if the collimation looks ok, but if it is shown to be out it is better to accept the collimation is out and to just enjoy the views the scope provides in its uncollimated state, and then attempt collimation of the secondary the next day during daylight.

    • Like 4
  10. 9x50 RACI plus some sort of red dot / Rigel / Telrad is pretty much standard on any large scope. On your Mak you probably want to save weight if possible so the Rigel or the Explore Scientific mini Telrad would be good choices. I would probably still go for a 9x50 over a 6x30 as there is a fair difference between the light gathering capabilities of the two finders.

    For your refractor it depends on what you've got and how wide a field you can get from an eyepiece. If you can get over 3° then you can probably get away without the RACI. 

    As for light pollution filters, the Astronomik CLS used to be a good one, but with the increase in LED lighting it is hard to recommend any light pollution filter these days. 

    • Like 1
  11. 58 minutes ago, Nikolai De Silva said:

    Is this out of collimation?

    It is impossible to tell. You need to place some light coloured card or paper behind the secondary mirror so that we can see where the edges of the mirror and focuser are in order to judge whether they are concentric. You also need to smooth down the foil on your collimation cap so that the entire surface looks bright. The dark dot formed by the eye hole should be inside the doughnut on the primary mirror but with such a large dark section in your cap the hole is not visible.

    1 hour ago, Nikolai De Silva said:

    And also how to adjust the the secondary mirror where no bolts are there?

    The three outer bolts are recessed and need adjusting via a suitably sized hex/allen key.

  12. 1 hour ago, Neutrinosoup said:

    Is it usually as easy as this!

    No, you would usually have to adjust both mirrors. However, what you have described makes sense. When you collimate with a laser any error made in the collimation of the secondary will result in double the error in the primary collimation. It sounds like your scope was collimated in the factory and during transport only the secondary moved, hence you saw that the secondary was out and the primary was further out. When you fixed the error in the secondary it also fixed the larger error in the primary because in reality that error didn't exist, it just appeared to due to the error in the secondary.

  13. Jupiter is very susceptible to atmospheric seeing, which is the stability of the atmosphere, not the darkness of it. In fact many people report that their best planetary views occur when there is a light haze in the air as there is no wind to blow the water vapour away. Due to this requirement for stable air, observing from a dark site will not necessarily show better results than observing from home, other than avoiding any negative effects from the heat haze coming off roof tops. Given the recent weather I would not be too concerned about any potential lack of sharpness over the last couple of weeks and would simply continue to observe without worrying too much about the collimation of the telescope or any other tweaks that may improve its performance. 
     

    One important section of atmosphere that is often overlooked is the air inside the telescope itself. When moving a telescope from a warmer location to a colder one there is a cooldown period where the components are cooling and this leads to air currents inside the telescope. For a 5” Newtonian this isn’t very long but within the first half an hour of observing I would consider this a possibility and see if the sharpness improves later in the session.

     

     

    • Like 3
  14. There is no 6mm Starguider, but there is a 5mm. The 5, 8 and 12mm Starguiders are well corrected even in fast scopes whilst the longest focal lengths are best used in slow telescopes. This means that in the specific case of the 5mm Starguider vs the 12mm Starguider + Barlow there will be very little difference between them. However, as a general rule if you are using a fast telescope and cheaper eyepieces then adding a Barlow can often improve the correction of the eyepiece. 

    I would choose a 5 and 12 over a 12 and Barlow as the eyepieces will be more parfocal, but if you were buying three items then there would be a good argument to buy 8, 12 and a Barlow so that you effectively have 4, 6, 8, 12 instead of buying 5, 8, 12, assuming that 4/5/6mm focal lengths are suitable for the telescope you will be using them with. 

    • Like 2
  15. 1 hour ago, Neutrinosoup said:

    Considering 1 or 2 for a small travel case when I visit my parents, Delos are big…..and I only have the 24mm panoptic 

    Option 1 = Get the Baader zoom….

    Option 2 = Take my Panoptic 24, and buy Delite 11/13 and Delite 5/7

    (For use with a 72mm apo, focal length 430)

    I have a 72ED and use 24 Panoptic, 13 Delite and 3-6 Nagler zoom. The only change I might make is to swap the 13 Delite for a 13 Nagler T6, which is also a small eyepiece. 

    Given you currently use Delos I think you would be disappointed with the correction level and reflections in the BHZ at f6.

  16. 11 hours ago, Lung said:

    Thanks again all. It does sound like a Mak is the way to go. The 102 is fine budget-wise, while the 127 is a bit more of a stretch once you add in mount, tripod etc. Will the benefits of the 127 over the 102 be noticable to a total beginner like me, or are they the kind of thing you'd need experience or different eyepieces etc to appreciate or make use of? There seems little point spending the extra now if the larger scope only comes into its on by spending more on accessories, or by having used it for several years first, but conversely if it really improves things for a beginner then it becomes worth the extra money from the outset.

     

    The benefits of the 127 lie in its larger aperture. The aperture of the 127 is approximately 25% larger than that of the 102 which translates into a 25% better resolution for planetary targets, 55% brighter stars and a 25% increase in optimum magnification on all objects. The previously posted field of view images don't really show this difference too well. When you look though the eyepiece the apparent field of view is the same, so the different circles appear to be the same width, with all the contents magnified that little bit more. Setting up the various scopes and eyepieces in the desktop version of Stellarium would show this more clearly. As a beginner you won't notice the difference simply because you don't have any point of reference but I think if you had the two telescopes side by side you would see the difference. If I were buying myself one of these telescopes as my only telescope I would go for the 127 but in my current position with a larger telescope I would also be happy with a 102 as a planetary grab and go option.

    11 hours ago, Lung said:

    With that in mind, is there a recommended 102 and/or 127 Mak to go for? I see there's the Skymax, the Messier and I think a Celestron, so do any of those stand out or is a case of finding the best deal on any of them? Or have I missed one from a different company i should be looking at?

    The Skywatcher and Celestron models are made by Synta so they should be the same with some minor differences to the fixtures. Ed Ting has recently done a review of the Skymax 102 that you might want to watch. Note that any visual DSO views will be small grey smudges nothing like the colour images he manages to get by sticking a camera on the end for hours and doing lots of post processing. The Bresser Messier scopes tend to be a little bit better mechanically, but optically probably about the same as the Synta scopes. The one difference between the two manufacturers that is notable is that the Bresser scopes are f/15 whilst the Synta scopes are f/13 so for any given eyepiece there will be a slight increase in magnification with the Bresser and a slight increase in field of view with the Synta. It probably means that the Bresser is slightly better for planetary but the Synta is a bit more of an all round scope. Any of these scopes would be a good choice and you're probably best off choosing whichever one comes bundled with the mount that you want to get.

    • Like 1
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  17. 9 hours ago, Vinnyvent84 said:

    Can someone give me some advice / insight? I have a Nexstar 6SE living in a Bortle 8 zone in NYC. Would upgrading from a ES 2x Focal Extender to a Televue Powermate 2.5x show a worthy difference for lunar and planetary visuals?

    Looking at your other posts your eyepieces are a 32mm TV Plossl, a 8-24mm BHZ and a 7mm X-Cel LX. With your f/10 SCT the only eyepiece that you can really use the 2X extender with for planetary is the 32mm Plossl, to emulate a 16mm Plossl, which is too low a magnification. For planetary you will want to be using the 8-10mm part of the range of the BHZ and (maybe!) your 7mm X-Cel LX. Setting your BHZ to 12mm and using it with the extender is almost certainly going to degrade a planetary image in an SCT, but might be useful for splitting double stars.

    So no, you won't see any increase in planetary performance by upgrading to the TV Powermate, because either extender should remain in its box during those observations.

  18. 4 hours ago, GasGiant said:

    Am I right in saying that the smaller the number the MORE powerful the lens ?

    Yes. The magnification given by any particular combination of eyepiece and telescope can be found by

    magnification = focal length (telescope) / focal length (eyepiece)

    so the shorter the eyepiece the higher the magnification. 
     

    4 hours ago, GasGiant said:

    Were as a larger number will give a wider field of view but have less sharp detail ? 

    If the apparent field of view (AFoV) of each eyepiece is the same then the true field of view (TFoV) will be larger in the eyepiece with the longer focal length. If the apparent fields of view are different then it may not be true. You can approximate the true field of view using 

    TFoV = AFoV / magnification 

    or substituting in the previous equation

    TFoV = AFoV * FL(eyepiece) / FL(telescope)

    Sharp detail is a lot more complicated as it is limited at low power by aberrations in your eye and diffraction at high power so you can’t say either high or low power is sharper. 

    As for eyepiece suggestions I would suggest getting a DSO eyepiece that will give an exit pupil in the 2-3mm range which in your telescope means an eyepiece with a focal length in the 10-15mm range. 

    For planetary a 1mm exit pupil is a good starting point, so a 5mm eyepiece, but this will give you 240x which may be above atmospheric limits some of the time so I would suggest a 7mm in addition to this. 

    The 5/8/12mm BST Starguiders will work well in your scope and I believe the OVL Nirvanas excluding the 16mm will also work well in your scope so you could get the 5mm Starguider and the 7 and 13mm Nirvanas. 

    Alternatively, the 3-8mm SvBony Zoom has been getting some good reviews recently, especially in the 5-8mm part of the range, so would work well for your planetary eyepiece and you could get this instead of the 5 and 7mm individual eyepieces. 

    • Thanks 1
  19. 1 hour ago, Lung said:

    Would a 102 Maksutov fit this bill? Or something like an Evostar 102?

    I think a maksutov will be better than an achromat for planetary but have a narrower maximum field of view for wide star fields. The 127 mak would perform better than the 102 and seems to be the Goldilocks size for the mak design. 
     

    1 hour ago, Lung said:

    Is there such a thing as dual controls, like a Go2 mount but with hand controls too so it can be used with no power or plugged in?

    The skywatcher AzGti mounts are controlled from your phone or tablet but have dual encoders so you can move the scope manually without losing alignment. However, I’ve not used one to know how well they work in manual mode. Both the 102 and 127 Maks are available on this mount. Note that some of this range are AzGte rather than AzGti, which means that they don’t have the dual encoders.

    I think you will need to go outside for the phone to pick up gps in order to use the goto system and aside from the window glass degrading the view, the chances of a planet being in the right place to view from inside through a window is very small. Using a goto system with children is often recommended as it means you can move quickly from one target to the next without the children getting bored waiting for you to find it.


    If you don’t want a full goto system then the Celestron Starsense Explorer is a manual system that you can attach your phone to to aid with finding objects. However, the mounts are not so well regarded and there are no maks in the range. 

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