Reddit mentions of Astromania 1.25" Extendable Camera Adapter - for Either Prime-Focus Or Eyepiece-Projection Astrophotography with Refractors or Reflector Telescopes - Threaded for Standard 1.25inch Astronomy Filters

Ok, so first off, this is not a good setup for astrophotography. The mount is not suited for it and the scope is not intended for it. That said, there are some things that might work within limits.

The primary limit here is the mount. This is an alt-az mount, and, as such, is not realistically capable of long exposure imaging. This means that deep sky photography (nebulae, galaxies, star clusters) is not an option with this arrangement. For those targets, you need long exposures (typically > 1 minute, often much longer), and this mount just can't handle that. You can, however, capture images of the moon and planets (Mars, Jupiter, and Saturn), though the planets may be tricky.

The next issue is the scope. Most Newtonian telescopes that are not specifically intended for imaging have a problem with focusing. If you want to understand why, I've written that up here. Also, with the smaller secondary mirror of the average Newtonian, you end up not getting full and even illumination of your camera's image sensor. Still, for the moon and planets, you may be ok.

There, as you appear to be learning, two main types of imaging: prime focus and eyepiece projection. Prime focus is usually the better option. The primary benefit of eyepiece projection is higher magnification. This is not always a good thing. I'll circle back to this.

With prime focus, this arrangement may just not work, as per my link above. However, the addition of a Barlow lens may do so.

I googled the adapter you have and found this. With the T-ring for a Canon camera you then have 3 pieces: the t-ring itself, the 1.25" nosepiece (the portion that inserts into your focuser), and the adjustable barrel that can accept an eyepiece for eyepiece projection. For the time being, I would recommend you sit the eyepiece projection portion on the bench and continue ONLY with the nosepiece and t-ring.

Now, if you attach these to the camera and then attach the camera to the scope, the focal point is probably still too far inside the focuser tube. you have to get the focal plane to the image sensor, and if the focal point is inside the focuser tube, you'll never get there. You need to push it out further.

This is where the Barlow comes in. The Barlow effectively increases overall focal length, and typically will push the focal point outward a bit, usually enough to allow the camera to reach focus. However, if you have that long adjustable tube in there, odds are it won't push the focal plane out that far. By dropping that tube and just using the adapter with the Barlow, you're probably going to be able to reach focus. Note, you mentioned "with or without the lens at the end of the barlow" - without that lens, you probably just have an empty tube, which works great as an extension tube if you ever need it, but is exactly what you do NOT want here.

You mentioned you have both a 2x and a 5x Barlow. Most Barlow lenses are not all that high quality. Some are, but you usually have to shell out more for them. For simple visual observing, they're usually ok, but they're not likely to be all that great for photographic use. Especially that 5x. Unless it's a TeleVue (and I doubt you bought one of those), it's likely to not be all that helpful. Further, odds are you're going to be pushing your magnification beyond the useful limit.

The Astro fi 130 has an aperture of 130 mm and a focal length of 650 mm. The T5i, also known as the 700D, has an APS-C sensor with an array of 5184x3456 pixels. When paired with your scope without a Barlow, if it could focus you would get a field of view about 1.96° by 1.31°, or 117.6' x 78.6' (arcminutes), which means a pixel resolution of 1.36" (arcseconds) per pixel. With the 2x Barlow, you get about half of that, so 58.8' by 39.3' with pixel resolution of .68" per pixel. Here's where you start getting into trouble.

Due to diffraction, the amount of detail you can get out of an optical system is limited by the aperture and the wavelength of the light being collected. For a 130 mm telescope, the diffraction limit for visible light ranges from about 0.74" for the extreme blue-end of the spectrum (around 380 nm) to 1.36" for the extreme red end of the spectrum (700 nm). At around 460 nm or so, around the area where the human eye is most sensitive, the limit is about 0.89". This coincides with the Dawes' Limit, so I'll generally use that as a shortcut from here out.

What this means is that any detail with an angular size smaller than 0.89" is likely too small to be able to resolve even under the best of conditions. There's a bit of wiggle room here, but with a 2X barlow, you're exceeding the ability of the telescope to provide detail. This means that you're oversampling: the camera's resolution per pixel exceeds what the optics are capable of providing. Generally speaking, this is problematic as it means small errors in tracking and guiding can have a greater impact. However, since you're only able to do short exposures anyway, this shouldn't be as big a problem.

But it also means that even with the 2X Barlow, Planets won't look all that big in your image. At its closest approach to the Earth, Jupiter can get to be about 50.8" in diameter. At a pixel scale of 0.68", this means that an image of Jupiter would be, at most, 75 pixels in diameter. Not all that big.

If you go to the 5X Barlow, it improves a little. You get a field of view of 23.4" by 15.6" and a pixel resolution of 0.27" per pixel. This would make Jupiter appear to be about 188 pixels across - much bigger, but still pretty small. And at that size, you are dramatically oversampling. While it would appear bigger, it would appear noticeably less sharp and detailed.

Adding in eyepiece projection just muddies things more. The smallest details you can see haven't changed, you're just making them bigger and blurrier.

There is a way to improve things, however. To do this, instead of capturing single exposures, you want to capture video and process using stacking software like Registax or Astrostakkert.

Stacking will do two things for you:

First, the basic use of stacking gives you the best possible image from a set of samples. In essence, it's a statistical analysis of a group (stack) of images. After you line up each image so that the same part of each image is directly above the same part of an underlying image, you then look at each pixel location in the stack. You take the same pixel location from each image and average their values. In theory, this provides the most likely "correct" value for that pixel. Often a weighted average is used. First the mean and standard deviation are calculated, then any pixels that are more than one or two standard deviations above or below the mean are discarded, and the average is re-calculated from the remaining values. This removes outlier values that might skew the analysis. Once you have that value, you do the same with each other pixel, and you end up with a picture that's made up of the average values of each pixel in the stack and, therefore, something that most likely represents the "true" image.

With other stacking techniques, such as lucky imaging, speckle interferometry, and drizzle, you can actually interpolate a deeper level of resolution. The larger the number of samples, the deeper the detail you can resolve. There's a limit, of course, you're not going to get Hubble-level detail, but you can easily increase your resolution several times above the native pixel resolution.

However, it's not as easy as just clicking a button and waiting for it to spit out a perfect image.

Additionally, the size of your pixel array and, thus, the size of the images you're capturing is not helpful. You're best off using the smallest image size you can. For video, your camera should allow you to do 720x480 resolution. This gives you an effective pixel resolution of 1.91" per pixel, which is under-sampled. But, the key thing here is that the stacking process will allow you to recover that detail. Still, for planetary imaging, this camera isn't the best option.

A much better option would be to get a cheap webcam and hack it to work. This basically requires removing the lens housing and attaching something to act as a nosepiece. If you have access to a 3D printer, you can do this pretty easily, or if you can get an old 35 mm film container (those old black containers with the gray lids that 35 mm film came in), you can toss the cap, cut off the bottom, and glue the webcam to the top, then run it through a laptop and capture video at around 30 fps. The total cost of this arrangement is likely to be under $20 and will do as well or better than your T5i. As an added bonus, removing the lens housing should also remove the built-in low-pass filter that nearly all cameras have and which blocks longer wavelength light. This makes it more sensitive to the near IR range of the spectrum, which is generally preferred for AP (though not absolutely necessary for planetary imaging).

Overall, as you're probably coming to understand, AP isn't a point-and-shoot game. It's damnably complex and getting even semi-decent images is often a tricky undertaking. Except for the moon. Nearly anyone can get a decent image of the moon.

My last suggestion really should be the first: join a club. Find a local astronomy club or society and join up. There's almost certainly a few people doing imaging in the club: get to know them and learn more about how they do what they do and why they do it that way. It'll make a huge difference.

Equipment:

• Orion Starblast 4.5 EQ Newtonian Reflector (450mm focal length, 113mm aperture). Standard aluminium tripod that comes with it.
  
• GSO 2x Barlow Lens (Turns out without the Barlow, the image plane of the telescope lies too far down the focuser for the camera to be able to focus properly. With the Barlow, it can focus nicely.)
  
• Astromania camera adapter (it has an extendable bit that can be used for eyepiece projection, but I wasn't using the whole thing, no eyepiece, just the Barlow)
  
• Nikon D7200
  
  Camera settings:
  
  
• ISO 100
  
• 1/30s exposure
  
• RAW, max resolution (6000x4000 pixels)
  
  Processing:
  
  
• Some mucking about in Lightroom, I don't really know what I'm doing there. The wife uses it and she's taken the little one to visit her parents (hence why I had time to play).
  
• Also quite a bit of cropping and combining the two images into one.
  
  ​
  
  My actual first attempt at astrophotography, I've been a regular observer for quite a number of years but I only got hold of a camera adapter a little while ago. There were some challenges, mostly that the camera that I've got is too heavy for the lightweight telescope. A heavier counterweight (or a longer bar) might help to an extent. The camera adapter was in fixed mode for this image. I tried to put it into the extendable mode as shown in the link, so that I could include a 6mm eyepiece to try and get more magnification, but then it became physically unstable, and try as I might I couldn't get anything to show in the camera's viewfinder or on the screen. With the adapter in fixed mode though, it was easy enough. The standard rack & pinion focuser that the telescope came with was also somewhat fidgety to focus, but using the camera's live view and zooming right in to the planets themselves, I think I did alright.
  
  
  Would be happy to hear feedback from more experienced veterans! I know my equipment is not the best, I've had it for years though and acquired most of it when I was a student on a limited budget (not that I have much of a budget for toys nowadays...). I'm quite pleased with the results given the limits of my skill and resources though.

Thank you so much for the help! Watched a few youtube videos on it and that also helped, thank you for the suggestion. If you wouldn't mind checking this and letting me know if I need anything else if you have any time, I would highly appreciate it.

mount

Telescope tube rings (Does the size matter, like is there a way to tell if it's good for the telescope or not? this is my telescope

mounting plate

[T-Ring adapter] (https://www.amazon.com/gp/product/B0140U9IWQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) (The camera I am using is a Nikon D750)

camera adapter

And possibly this autoguider

Once again, thank you for the help.