[su_button url=”https://polywogg.ca/a-polywogg-guide-to-astronomy/” style=”glass” size=”6″]Back to the Table of Contents[/su_button]

Download the PDF version

[su_box title=”Executive Summary” style=”soft”]The sky is huge and your scope shows only a small portion. Since not all the portions are equally interesting, you need to be able to find fun objects through three steps – aligning your finder tool, aligning your telescope, and navigating the sky.

Aligning a computerized mount (PushTo or GoTo)

  1. Assemble and level scope, align finder tool.
  2. Enter GPS coordinates, time and date.
  3. Point to any three stars, two specific stars, or Polaris.

Aligning an equatorial mount

  1. Assemble and level scope, align finder tool.
  2. Point the axis North or at Polaris.
  3. Align using latitude scales (adjusting altitude to match your latitude), pointing at Polaris, or using Polaris finder scope (match view to current position of North celestial pole).[/su_box]

Preparing to view the sky

In order to find interesting objects in the sky, you need to be able to do three things:

  1. Align your finder tool to your telescope (PWG-A0008);
  2. Align your telescope to the sky (PWG-A0009); and,
  3. Navigate the sky to various objects (PWG-A0010).

Each step has some sub-options, and there is no “one best way”. You will need to find what works well for you and your scope.

STEP 2: ALIGN YOUR TELESCOPE TO THE SKY

While I said there are three steps, not all scopes HAVE this step, and none of them REQUIRE this step. Before you celebrate and move on, skipping this step dramatically limits your options in the navigation step. Oddly enough, it is not the scope that determines if you can do this step, it is your mount. Basic Dobsonian mounts and alt-azimuth mounts have no settings to adjust, it is literally assemble and go, which means these scopes are generally excluded from this step. By contrast, equatorial (EQ) mounts and computerized mounts CAN and SHOULD be aligned. There isn’t enough space here to cover all types of mounts and setups, so I will cover the basic steps for each.

Aligning a computerized mount (PushTo or GoTo)

The mounts with computers usually have a full database of where up to 50K, 100K, etc. objects are in the sky. Which is great, except it doesn’t know where YOU are, so you have to tell it where you are and what you can see. The various software and menus are different for each model of device and I can’t cover each of them, so this description has the three generic steps. For those interested in a detailed GoTo setup, see PWG-A0011 for the setup and alignment of a Celestron NexStar 8SE.

Here are your steps:

  1. READY: Ensure that your scope is set up properly, it is level, and you’ve already aligned your finder tool;
  2. AIM: Start your automated procedure and enter your location information (GPS coordinates from a smartphone or Google Maps, date and time, time zone, and daylight savings) to tell the computer where you are; and,
  3. ALIGN: Point the scope at three generic stars and let the computer figure out which ones (three-star align); point the scope at two specific stars chosen by the computer (auto two-star); point the scope at two specific stars chosen by you (manual two-star); or point the scope at Polaris (polar alignment).

Assuming the mount was level, and that you entered the info correctly, the computer should be able to do the math to now find everything in the sky. Rough estimates gives you rough alignment; careful settings and adjustments gives you good alignment.

Aligning an equatorial mount

An equatorial mount doesn’t have a computer so you can’t do a generic three-star, auto two-star, or manual two-star alignment. Instead, you “tell” the scope where you are in relation to the sky by pointing it at a specific object that doesn’t move, Polaris, which is the North celestial pole (i.e., a seemingly fixed point in the sky…while it is not 100% fixed relative to the Earth’s rotation, it is close enough.) By pointing your scope at Polaris, you are telling the scope where you are in relation to that fixed point, and thus the physical setup will know where everything else is relative to that point.

Here are your steps:

  1. READY: Ensure that your scope is set up properly, it is balanced and level, and you’ve already aligned your finder tool;
  2. AIM: Get your scope’s axis pointing either north or roughly at Polaris;
  3. ALIGN: There are many different types of equatorial mounts, but the various polar alignment methods involve latitude scales, pointing at Polaris using the finder and scope, or using a separate “polar finder scope” tool.
    1. Latitude Scales in daylight (basic alignment): Point the axis due north (using a known landmark or a compass). Adjust the “altitude” settings until it matches the latitude of your location (my latitude is 45.4215 degrees North, so I would set it to 45 degrees). Once done, I am roughly aligned.
    2. Pointing at Polaris in the dark (medium alignment): Point the axis of the scope north. Loosen DECLINATION knob and move telescope so parallel to axis (setting circle will read 90 degrees). Lock DEC and RA. Using just altitude and azimuth adjustments, find Polaris in the finder tool (red dot, telrad, finder scope – obviously, in order to do this step, you need to be able to see Polaris in the night sky and know which one it is…this is usually done by spotting the Big Dipper, and then using the two stars on the “right side” of the pot/bowl to point to Polaris by going from the bottom of the pot (Merak) to the top of the pot (Dubhe) as “1 unit”, and continuing in that direction for five more units to get to Polaris). ** Don’t change DEC or RA orientation, just the alt/az settings to get Polaris in your finder scope. ** Once found, your scope is “aligned” to Polaris.
    3. Using a separate Polaris finder scope (full alignment): Some mounts come with separate finder scopes specifically designed to help you align. However, unlike normal finder scopes attached to the scope, alignment finder scopes are built into the mount itself. The exact steps vary by model, but essentially you first move your scope on its side (i.e., out of the way) so you can “see” down the axis. Then you do rough align to get Polaris in your little alignment finder scope (it may also show you Cassiopeia or the Little Dipper in the image too). To do full alignment to the North celestial pole (NCP), you can use either online apps (on a smartphone) or print out alignment maps ahead of time that tell you where the NCP is in relation to Polaris. So, you adjust what you see to put Polaris in the same spot, and the NCP will be centred. Done.

[su_box title=”Tips” style=”soft”]While you can use any scope without doing an alignment, equatorial (EQ) mounts and computerized mounts CAN and SHOULD be aligned.

Full polar alignment is best if you are doing any astrophotography.

Polar Alignment in the Southern Hemisphere is harder because there is no bright star like Polaris so close to the celestial pole. You can align using: the latitude scales method; Sigma Octantis (just like you would with Polaris, except it is way fainter); or an intersection between a line from Alpha Crucis and Beta Crucis (in the Southern Cross) and a right angle line from Alpha Centauri to Beta Centauri.[/su_box]

Share