# How is FOV calculated in astrophotography?

FOV = ((57.3 / 1040) * 22.3) The long side of the frame has a field of view of 1.23 degrees. Example: A Canon T2i (550D) has a sensor that is 22.3 x 14.9 mm.

## How is FOV calculated in astrophotography?

FOV = ((57.3 / 1040) * 22.3) The long side of the frame has a field of view of 1.23 degrees. Example: A Canon T2i (550D) has a sensor that is 22.3 x 14.9 mm.

### Can you use a Barlow on a guidescope?

I use a barlow for guiding and it works fine. A couple of things to watch out for though. First, if you have a small guidescope, using a barlow may cause the guide stars to become unacceptably dim. A barlow increases the effective focal length, which means it also effectively increases the f-ratio.

How do you find the focal length of a reducer?

If you have a 0.71x focal length reducer, you simply multiply the focal length of the lens by 0.71. E.g. 50 mm lens on 0.71x reducer = 35.5 mm lens. The “crop factor” doesn’t affect the focal length. Also, the focal length is not the physical distance from the front of the lens to the sensor.

What is focal ratio on a telescope?

The third key specification of a telescope is the focal ratio, which is the focal length divided by the objective diameter. A long focal ratio implies higher magnification and narrower field of view with a given eyepiece, which is great for observing the moon and planets and double stars.

## What is the focal length of the planets?

Good telescopes for planetary imaging start at around 2000mm focal length and up. Aperture is also important, as the larger the aperture, the more resolution on planets can be resolved. Unlike with deep sky imaging, telescopes with slower/longer focal ratios are preferred, such as f/10.

### What is a good resolution for telescope?

Resolution of the telescope The Hubble Space Telescope has a best resolution of about 0.05 arcsecs. That’s about the apparent thickness of the unfolded paper clip almost 2 miles away.

What is a focal length reducer?

A telecompressor or focal reducer is an optical element used to reduce focal length, increase lens speed, and in some instances improve optical transfer function (OTF) performance.

Is 700mm focal length good?

Yes indeed, a 60mm refractor with a 700mm focal length is most definitely ‘good enough’! Chances are pretty good that the optical quality of your telescope lies somewhere within the good to excellent range! Some of us (myself for one) started out with a telescope of similar size.

## What is a good focal length for a telescope?

A good all round first telescope should have a focal length of around 1000mm to 1200mm. All refracting telescopes use a glass lens as their primary focusing unit.

### How big is the finderscope on the Explore Scientific ED80?

With a focal length of 480mm, this high-quality instrument can easily fit the entire Andromeda Galaxy in a single field of view, as well as M8 and M20. A common question I get is about the finderscope bracket on the Explore Scientific ED80.

What type of guidescope should I use with the ED80?

I would suggest using the Orion 50mm guidescope in the stock finderscope rings included with the Explore Scientific ED80. The small weight and size (7.5 lbs., 18.5″ long with dew shield) of this instrument make it the ultimate grab and go telescope.

How do I attach an autoguider telescope to the ED80?

Most users who intend to use the telescope for astrophotography will be connecting an autoguider telescope and camera to increase the precision tracking of the equatorial mount. Rather than attaching a separate bracket to hold this autoguiding telescope, I simply use the existing bracket that was designed to house the finderscope on the ED80.

## What is the best focal length to take pictures of nebulae?

The 480mm focal length seems to be the “sweet spot” for capturing large, wide-field views of nebulae and large galaxies. From the moment that first exposure of the Orion Nebula appeared on the camera screen of my Canon 450D, I was in love with the image quality produced by the Explore Scientific ED80.