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Not sure what are you asking? Image orientation depends on how you rotate your camera with respect to telescope and also what type of telescope you are using. Some telescopes invert both axis - thus creating effect of 180° rotation, while some invert only one axis (or invert both and then additionally invert one axis one more time - thus returning it to "normal"). You can set all of that in oculars plugin when you define scope and sensor. Additionally you have this popup menu accessible via ALT+O:

Hi and welcome to SGL. Closest ETA that was able to find is at FLO: https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-eq-5-pro-goto.html They say it is due in 15-20 work days. Other retailers mention something February / March next year. However, best to check with FLO directly to make sure it is indeed available in 15-20 days as I was waiting (and still am, but it is in stock now as of yesterday so hopefully will be send out first thing next week) on item for 2 months now although it said 20-25 work days.

Ideally, you want at least number of measurements, average value and standard deviation to be able to tell how accurate some measurement is. Generally published catalogs don't often include that information, but if you search scientific sources, you'll get bunch of additional information on measurement in particular catalog. For example, here is screen shot of VizieR search on random mag 6 star that I picked (SAO 55330) - Hippocaros Main catalog: Same star in ASCC: http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-source=I%2F280B%2Fascc&recno=462590 Shows error in V magnitude to be 0.008mag:

Hi and welcome to SGL. This is quite normal - raw data from camera is not color balanced. Moon is easy target to balance - just make sure it is neutral grey overall. Boost blue and red components until you get good color balance. It can be done in post processing and I would say - that should be preferred way of doing it rather than messing with on camera color balance controls.

It is just down to measurement error. Difference is mag 0.008 which translates to ~ 0.74% of difference in brightness - or less than one percent. If you want to do comparison - use either as you won't be able to tell much larger difference than less then one percent of brightness difference.

Is equivalence of gravitational and inertial mass one of those things that any substitute theory of gravity needs to explain? As far as I understand, equivalence stems from the fact that there are no two different things - there is just inertial mass. Other part is down to energy / mass equivalence (one that bends the space - it is energy that bends the space).

Indeed, field stop needs to be positioned at focus plane - then it is in focus. Blurred field stop just means it is a bit out of focus and needs to be moved to exact focus to be sharp.

Don't know why everyone keeps blaming gravity for this, when it clearly states that both hammer and feather fall with same acceleration. Remember that next time you drop feather on your foot

You can easily test if it is the field curvature (and I bet it is). Concentrate on center of the field - focus stars to pin points - edge stars will be out of focus. Concentrate on outer field - focus stars there to be pin points - center stars will be out of focus. If above is true - you are dealing with field curvature. If you can't do this with very well corrected eyepiece (19mm Panoptic) and outer field is still not sharp but rather small crosses or something like that - then your scope has astigmatism. You should perform star test at high power to see what might be the problem. By the way - large exit pupil can indicate problem with your eyes as well - but in that case, stars will look elongated / distorted all over the field - not only at the edges.

Here is alternative to consider. I have some of the 82° range (11mm, 6.7mm) but also a little bit less wide line - 68° 28mm. I prefer less wide eyepieces for wide field. I'm ok with 82° being planetary eyepieces in my dob - gives you more "drift" time before nudging the scope. Overall, best AFOV size for me is in 60°-70° range. If you decide to mix eyepiece, then alternative to 30mm 82° in terms of sky it will show would be this one: https://explorescientificusa.com/collections/62-series-eyepieces/products/62-40mm It has 42.2mm of field stop (43mm for 30mm 82° - so very close) and it is relatively light weight compared to others at 670g. Not sure about edge performance in 40mm, but I do have 5.5mm and it is nice eyepiece that is easy to use and good sharp performer in the center of the field (I used it as planetary EP and did not pay much attention to edge of the field).

On a slightly different note - I just realized there is this eyepiece: https://www.firstlightoptics.com/astro-essentials-eyepieces/astro-essentials-super-plossl-eyepiece.html 56mm 2" Plossl. I know that it is not wide eyepiece - but it is wide field eyepiece - it will show you as much of the sky as any other 2" eyepiece. How much of a problem is this focal length? Again, at F/10 - it will be ok with 5.6mm but at F/7 it will provide 8mm of exit pupil and that is wasted light for most people. Also, I'm guessing that eye relief will be too much?

I think that you'll find Evostar 72ED very demanding on eyepieces. This is not as much due to being faster scope at F/5.8, but because of very short focal length. Such a short focal length will produce very curved field and not many eyepieces can deal with that. Good thing being that you are still young, if I remember correctly - most people start having trouble with not being able to adapt to shifts in focus position after age of 50 or so. This means that your eyes will compensate for most of field curvature. Other way of dealing with that is of course use of field flattener. Though these are mostly used for imaging - some people use them on short focal length scopes to get flat field. Not sure if you should select your eyepiece to work with both scopes - maybe aim just at 4" F/7. At 420mm - Evostar already offers quite wide views and if you want to get widest possible view at 70mm of aperture - to go "ultra wide" - there is a cheaper solution, get one of these: https://www.teleskop-express.de/shop/product_info.php/info/p2005_TS-Optics-11x70-LE-Porro-Prism-Binoculars---perfect-for-twilight-and-night.html although you already have 15x70 - that is just a tad smaller FOV.

If it is TS scope - then it is made by GSO. In any case - it won't be any more difficult to collimate or different than other F/5 scope.

Sidereal rate has nothing to do with time taken to orbit the Sun. It has to do with Earth's rotation. There are usually three different tracking rates - Solar, Lunar and Sidereal. Sidereal is "pure" earth rotation rate and is used for fixed objects like stars, but also for planets - because they don't move much during single day and their proper motion simply can't be perceived as motion at the eyepiece (it takes several hours for planets to move just a tiny bit with respect to background stars). Lunar tracking rate is combination of Earth's rotation and also Moon's orbital speed around the Earth. Solar tracking rate is combination of Earth's rotation around it's axis but also orbital speed of Earth around the sun. Guiding has nothing to do with above rates - it is designed to deal with couple of things - primarily imperfections in mechanical components of the mount. These are not perfectly circular and mount does not track perfectly well. Guiding is needed for long exposure astrophotography because these imperfections result in stars being smeared instead of points. It also deals with polar alignment error and refraction in the atmosphere. It is not needed for observation, nor planetary imaging since involved "exposures" (remember that we can watch movies because we "see at about 30fps") are far too short. Fact that DSOs move out of your eyepiece will most likely have to do with a) wrong tracking rate selected - lunar or solar instead of sidereal b) very poor polar alignment

I think this might be mild case of google-translathitis and not ill intent?

I think it is good first scope for things you intend to do with it (lunar and planetary). Not a bad idea - just make sure you keep it safe from moisture. You'll need a dew shield for this scope - both because of the dew issues that you might have sometimes, but also because of telescope construction - good dew shield will enhance contrast as it will block any stray light falling on front corrector plate. Yes, you'll have to do it each time, but if you use scope visually - you won't need to do it very precisely so it will only take a minute or two each time (just make sure RA axis is pointing to Polaris). If your primary interests are Moon and planets - then yes, motor drive is a good thing to have - it lets you concentrate on observing instead of adjusting scope pointing every half a minute. It is also good if you plan to observe with partner - planets often slip out of view by the time you switch places at the eyepiece and then you have to search for it again (not major issue - but again, matter of convenience). These will be sufficient to start with, but after a while, I'm guessing you'll be wanting more options. Good options are: https://tavcso.hu/en/product/GSP32 As wide field eyepiece for that scope and these for higher magnification: https://tavcso.hu/en/productgroup/okular_planetary Just be careful not to get eyepieces below 7mm - as that will give you too much magnification for your scope. 7mm is fine and should be your highest power eyepiece, but less than that (6mm or shorter) - will be simply too much for your scope.

Looks like astigmatism to me rather than diffraction spikes. Pinched optics would produce this over whole field - if it's just corners, it probably has to do with field flattener / reducer. Maybe spacing, or tilt or similar.

I don't own that mount so I can't comment, but I've seen two different sites quote it at 5Kg capacity. I've never seen it quoted at higher payload. It did make me wonder - Skywatcher mounts have increasing payload as numbers go up - how come AZ5 has smaller payload capacity in comparison to AZ4.

I'd say that 6" CC has twice the weight of 127 Mak? First is 5.8Kg while second is around 3.2Kg. Mount itself handles about 5Kg of weight - CC will be pushing it. I guess AZ4 is probably better suited to this scope, or possibly EQ5 or SkyTee II.

It would be best to get a bit more background on dark matter first. Does not need to be very deep - simple reading of Wiki page on Dark matter can help put things into perspective: https://en.wikipedia.org/wiki/Dark_matter Here you can find list of major observational evidence in support of existence of dark matter: It is not just Galaxy rotation curves - it is much more than that. There is also evidence that goes against modified gravity theories - like discovery of galaxies with little to none of dark matter - those behave in accordance to GR and absence of DM. If DM required modification of GR - then such modification would hold everywhere - or it would need another "strange thing" to explain why there are galaxies that don't behave like modified GR tells they should. In assessing how successful GR really is - I think it's worth having a read about list of tests used to confirm it: https://en.wikipedia.org/wiki/Tests_of_general_relativity

Fixed objects (not planets) will hit max altitude at least once each day. It does not depend on date - it depends on time for each particular date

Today, it seems that math and I are not really on first name basis. As folk would say - third time is the charm, so let's give it another go I was almost right the first time - it is in fact summation but one needs to take 90° - latitude and not latitude. Since I'm on 45°, no wonder it worked for me as 45° = 90° - 45° In the end, I present correct formula - (90° - latitude) + declination = altitude of object at transition time.

Just realized I did the math wrong - I got the same result because I'm at 45° North - half way between equator and north pole. You actually need to "subtract" values rather than add. For someone at 50° North, Orion's nebula will be lower down not higher up. Proper math would be 90° - (-5° - 50°) = 35° altitude. It is 90 degrees minus (declination - latitude).

Just realized that observability plugin provides culmination info for "today" - you can use that as well.

Stellarium has "Observability" plugin that gives you following info: For "fixed" celestial objects (not planets) - you can figure out what height of above horizon will be - fairly easily. Look at declination of object and add your latitude to it. Orion nebula is ~ -5° of declination and I'm at 45° North. Orion will be at max altitude of 40° for me. It will be at this position (meridian, 40° alt) at midnight around Dec 15th. Further away from Dec 15th you are - it will be before or after midnight at this location.