When white light, from any object in the sky, or from a flashlight even, is refracted, it splits the white light into its component colours, as Newton had discovered and demonstrated with a prism...
Of course, the prism cannot convert those separate beams of colours back into a single beam of white light; but a refractor can, but to varying degrees of accuracy...
See that wayward beam of colour, represented in green? It didn't quite make it to the focal point, and as other two did. That wayward colour is what is seen through a shorter achromat; shorter than an f/15, I might as well say.
Achromats are the inexpensive refractors you find within the marketplace online. Many are short, some are long. The longer the achromat, the more accurately the colours are realigned into the white light emanating from an object in the sky. Conversely, the shorter the achromat, the more false-colour is seen when viewing brighter objects, and it gets worse as the magnification goes up, as it becomes magnified along with the image; the intensity. Achromats have been around since the mid-1700s, and up until relatively recently they were longer. I cast my head into my hands, and bemoan, "If only we might've kept the 'idea' of downsizing of so many other consumables out of the astronomical market." Everybody wants their playthings as small and compact as possible, and regardless of the performance-related consequences. Short, "fast" achromats are a regression of Hall's hallowed design; certainly not a progression. They are primarily for ergonomics, not optical performance, although something may be said for the low-power wide-field views that they provide, but only when observing the dimmer deep-sky objects and vistas.
You may not see that wayward beam of colour, but it's there, and damaging to the image. For the lack of a better analogy, imagine that you're building a house, and it requires three truckloads of bricks, but one of those trucks never made it to the site. Not to worry, as the house is built anyway, although incomplete as a result, and curious in appearance to boot.
With a single achromat, you'll have a choice of either ergonomics(shorter, more compact tube, softer images), or optical performance(minimal false-colour and sharpness).
With a single apochromat, you can have your cake(short, more compact tube), and eat it too(minimal to virtually no false-colour, sharper images).
Now, with refractors(and Newtonians), what you see is what you get: a short tube = a short focal-length; a long tube = a long focal-length. It's more difficult to reach the higher powers with a short focal-length, for meaningful observations of this sprite and that, given the general range of eyepieces from 4mm to 40mm. It might be easier to carry, handle, and to mount on a tripod...but...
A focal-length shorter than 650mm or so is not good for trying to reach the higher powers. Even with 650mm and 750mm focal-lengths, a 2x or 3x barlow combined with said eyepieces is oft required. Focal-lengths of 900mm and up, but not too much longer, play well with said range of eyepieces, and in observing most everything in the sky satisfactorily.
Keep in mind that a telescope, in the first place, is for seeing faraway objects up close, and a longer focal-length makes that possible, and easier.
Many are making a compromise with this one. It's not too long, per its aperture, nor too short, and at f/8 the false-colour should be tolerable...
For visual, the mount that's included, an EQ3-class, would be doable with a refractor of that size; if you don't mind the moment-arm effect(a shake and a wiggle here and there). An EQ-5 would lessen said effect...
...mounted onto this... https://shop.opticsp...AUaAgwDEALw_wcB
That's an EQ5-class mount, and a bit sturdier. If you'd prefer an alt-azimuth, you may have to go with one that's more costly than that EQ-5 in order to support that refractor.